That sounds like a good plan.. Apologies for making some very US-centric recommendations.. hopefully the ideas are universal enough though.
I have a few behind the switch relays and they work great - have used Aeotec and Fibaro, also have a zigbee relay for a closet light.. My style of switch is the "toggle" style which limits my smart switch choices a bit.. "paddles"/decora seem to be much more common for newer builds over here.
I’ll also say “leave the Hue on the Hue bridge”. Hue lights are disappointing without the bridge to enable their special features. If you use Homekit, enable “Adaptive Lighting” to get white light during the day and warm light at night. There is a community Homebridge integration as well for devices on HE.
Regarding adaptive lighting with Homekit: How does that work? The idea is still that you would just press a switch to turn the light on.
Regarding switches, I have a battery powered button or multi-button blue-tacked over the original switch in most rooms, which performs on-off as well as in some cases scene changes, of any smart bulbs in the relevant room. I didn't fancy wiring controllers for a couple of reasons 1) it seemed a hassle and switch wiring make my brain boggle, and 2) if we did move, we could just pack up the smart devices and the house would still be working as a normal house for anyone who moves in.
Unfortunately blue-tacking stuff over the existing switches is a complete non starter here. Will never get that past my partner. Basically WAF is very important.
Be warned that Sengled bulbs do not pair well in groups larger than 3 bulbs. They have unofficial, and spotty support for Hue Hub (if that is being considered), so they don't fully integrate well into the Hue system. And according to @justin.rodko, the performance and reliability of the bulbs in Hubitat is horrible.
There is a Sengled hub available that drives their bulbs, but it only integrates with Alexa, HomeKit, IFTTT, etc... There is no public API so any support for accessing the hub from Hubitat would be a crapshoot.
I find it absurd that every smart home company wants to make a hub and lock users into just their ecosystem. They would get more sales if their systems were openly available. Hue is still a leader in lighting hubs because they have public APIs that allow for local and/or remote integration. They started off tightly integrated to only their ecosystem and has learned the value of 3rd party integration. I gave high hopes for WiFi based solutions, like Govee, that have public API but are limited in features, to hopefully offer local control.
In my opinion, perhaps the best solution you will find for performance, and capabilities, will come from the new LiFX WiFi support in Hubitat, because of its tight integration with Hubitat now, and the HE developer's commitment to make this the preferred lighting solution.
There are issues with WiFi for smart home though. They require a router in addition to the smart hub. A single WiFi AP has a limit to the number of nodes that can be supported, and a single Ethernet network has a limit. Historically, the limit has been right around 128 devices, but thanks to switches, and MIMO WiFi technologies those limits have grown larger -- though the router may not handle all those WiFi bulbs, so that typically means a 2nd WiFi network for lighting.
For all local access, if I were to build my smart home from scratch all over again, I would do what I have already done, with a few tweaks. I would:
You can setup with one hub now, and grow it later. And hubitat is totally capable of being used in a single hub environment, which is how I have run things for years. But this recommendation comes from personal experience and lessons learned, and still being learned to this day, that have impacted the acceptance of a smart home by family members. The last thing you want is to struggle to figure out how to turn on / off a smart light in the middle of the night, during an internet outage, when your hub goes offline because of some random bad code in 3rd party apps.
My 8 recessed bulbs + 2 in table lamps in my den and my office table lights and some others would like a word with you then.. 
I have had 0 problems with the setup and have them grouped + zigbee messaging on.
Now I am running this on a C-5 but I think the ZB chipset is the same between C7 & C5.
edit1: also not sure why the left/right den table lamps are set to the generic driver.. will have to change that.. also note that my Z-Wave devices are on a separate hub - a C7.
edit2: Should ALSO mention that I run node-red so no local hub rules. Maybe that is the another difference.
They're using the proper Sengled driver - but likely were originally discovered and assigned the Generic - so it sticks around in the "Name" unless you change it
I have four candelabra Sengled bulbs in my master bedroom ceiling fan. They are all in a zigbee group. One (and it changes which one) does not behave correctly -- every time. Turn on, only three turn on, turn off, and turn on, and eventually the failing bulb changes to another bulb.
Pairing them was a pain too. I had to try several times. I have my hub 15feet away with only 1 wall between. Moving the lights to a little table-top candle light fixture, and placing 5ft from hub didn't change things. Maybe I need a firmware update, who knows? They don't offer firmware updates unless I buy their hub.
Not everyone has the same experience, and that is why I included a link to the same issues others have had. I wanted to make it clear that there are issues, and like all things, your mileage may vary.
Personally, I think my Sylvania Lightify are much better, and at a better price, as they worked out of the box, and no issues. And since I invested in Hue, they all went to my Brother-in-law, and the Sengled LEDs will go to a new home too when I get hue compatible bulbs to replace these, and can move the light fixture over to Hue.
Note also, that I did not mention in my response, my personal preference for the Hue system, and that I would keep hue, because I think the average user wants a smart home solution that works even when the hubs crashes, and hue makes this difficult without using a phone as a backup controller. It can be done with enough adjustments, just not easy, nor fun to setup and work out all the details.
Very cool - didn't know about these. Just ordered a couple to try in spots where the family sometimes forgets to leave the $@#(!@#$ switch alone! 
I hear you! All this means is... it's complicated. I have never used the candelabra lights - but have been curious as I have a chandelier that could use them (or a no neutral dimmer) so that is good info to know. My sengleds are either BR30 or A19s - I wonder if the smaller form factor impacts the electronics any.
Another option is a Zigbee dimmer that fits over the light switch, so you still have a perceived level of manual control.
These types of dimmers are getting harder to find, but this one from Lutron is a fairly new product, and easy to get. Makes a typical wall switch look like the paddle dimmer.
It works with color or color temperature changing bulbs. When the light is turned on, Adaptive Lighting changes it to the CT for that time of day. The part that sold me is that when the light is turned up, the color temp is also changed to whiter light (and warmer when turned down). This is especially nice at night when you need to find something because 2000K isn’t going to help you see very well.
They work well with HE, but they are amazing with Hue. I bought 10 of them when they were on sale.
Gledopto might be a good choice for the recessed lights. I only have experience with their RGBW controllers so I don't know for sure. One benefit with those is that you can link them to the Hue Bridge and use them with 3rd party Hue phone apps to sync to music. They'll also work with Hue Labs animations. The downside is that they can't be added to Hue "Entertainment Areas" so they can't be used with Hue Sync.
Edit: I should probably note, when using 3rd party bulbs with the Hue Bridge, there could be some funkiness. I haven't run into issues with Gledopto, but YMMV.
I personally didn't care for these at all. They just felt cheap for how much they cost and wouldn't stay on the switches I tried them on. I ended up returning them. Also, OP is in Switzerland, so those won't work for him. 
I bought one to use to create the Hue Integration for it for Hubitat. It's pretty cool, but creating an integration for it is a major PIMA. I had to put that feature on hold, at least until after the V2 API migration is complete... I too like it. It's a clever design.
Are there any issues with it running directly on the HE? I don't need any fancy dimming or other fine grained controls just on/off maybe a crude dimmer setting. Also have to see if it meets WAF..
The biggest one would be: if using the mirror me app, because HE sees the button as off/on, this can be problematic if the device you’re controlling is also controlled by something else.
I live in Switzerland in an old house that we are renovating. That adds a few challenges...
The space we have in the ceiling to install lights is only 5cm deep. So the usual GU10 shape bulbs one would use for down lights cannot be used. Using fixtures that protrude is not an option either as ceiling height is only 1m92 (Yes, old mountain houses in Switzerland are like that).
So we are stuck with flat fixtures, and because the ceiling is so low we prefer stuff that does not produce to much glare.
The Gledopto I liked, but I have an issue with my electrician. He insists that since the ceiling is wood the lamps we build in must have the MM mark, indicating you can install them in materials of unknown flammability.
So we are still looking for good lights.
Then there are the controls. Here we want to go for something that looks conventional as much as possible. So to switch the light on you just press a button on what looks like what everyone expects here a light switch to look like.
And here Switzerland does things a little bit different as well, and as a result, when it comes to switches and sockets there is one company that basically enjoys a monopoly here. Switches and sockets are put in wall boxes that are round (diameter 83 cm) or square (77mm on a side) and it is customary to have multiple of them together. My electrician put in lots of double boxes and extra ducting. So the standard wall box looks like this
And it is very common to have a combination of a switch and a socket. Great when vacuuming, as you do not need to bend down to plug the vacuum in.
Because of those vertical double boxes none of the usual Z-Wave or Zigbee switch/module combinations work. What does work is wire in a module in the back of the box, as they are quite deep. So hence my interest in Shelly Switches.
Now Feller (the Swiss company that basically produces the wall switches that are in pretty much every house here) has a Wifi system that is quite interesting. You have a module with a faceplate with a number of buttons, up to six, and the lower one operates the local load (eg. a dimmer) and the upper ones you can freely program do to things. Including operating other switches. The whole thing uses wifi. It does not need a hub, but it does require your network to be up for the special functions. With the network down you still have local control. Looks like really what I need to satisfy both my desire to tinker and my wife's for something that just works.
Those Wifi Switches all have their own Webserver, and an API that has been published. So like Shelly, but a bit more expensive. I do like the look though:
It will all come at a price, but on the whole remodel it is not going to add up to a lot...
Download the Hubitat app
