Absolutely! Last thing I want to do is just replicate stuff that did not work well before. That's why I started with just the stuff I had in hand. Besides, I can't afford to get all new stuff all at once! 
For garbage disposal an option is to use a stand alone Caséta switch + Pico. You'd also need a 120/120 contactor. This switch would not be attached to a Caséta bridge, so there is no unintended automation concern.
The relay on the ZEN30 is an on/off switch and NOT a momentary switch which is what you need for the garbage disposal. You can actually leave the regular double switch, keep the garbage disposal part as is (not smart, just manual control) and install a Z-Wave relay behind the switch for the light. We'll be releasing a new relay half the size of the ZEN51 in the next couple of month too in case space is a concern.
If you decide to pick up any Zooz switches, the next sale on The Smartest House starts on July 1 - that's when you'll get the best discounts 
Great! I think a smaller one will be a must, for this application. I will wait for this. And the discount info comes just in time. My favorite word is SALE. OK, second favorite. CLEARANCE is first! I will have to figure what I need in the next few weeks to be ready for this.
Just to chime in with a minority opinion, go with Lutron Caséta, as also suggested above by @aaiyar. You will never regret it. Each Lutron switch supports 3-way, too, so you will only need to replace one of the switches in each 3-way circuit. 100% reliable.
For 3 way, I recommend Invoelli. You need one smart and one aux switch. The Aux switch will behave just like the the smart switch minus the led indicator.
To chime in on Garbage Disposal automation - mine has been automated for a while now and it has never been an issue. I have it on an older on/off Inovelli switch that has a manual override tab on it, so if I want to be sure it won’t turn on on its own, I can pull it. I can also turn off the breaker to be extra sure, but never needed to do that…
It certainly makes it easier to turn on via Alexa or Siri when my hands are full or dirty!
I also have an automated faucet and set it to automatically turn on with the unit, and turn off when it was turned off. Has been useful!
As for toggles vs paddles - when I moved in this house over 15 years ago, it had all toggles. They were quickly all switched to decora style paddles, along with all the power plugs. A small investment that improved the looks substantially, and made my then future transition to home automation much easier!
Most homes actually have the disposal wired to a regular on/off switch. I changed mine to a momentary because they have them at the hardware store as a "Disposal switch". Seemed like a good idea, but its kind of a hassle sometimes to hold it down while pushing stuff in.
Also highly depends on what kind of disposal it is. There are some that are made to run while you feed them, and some that you fill up and then run to purge.
I have mine controlled via an air-switch. But power to the disposal is cut off if it runs for more than 3 minutes.
Mine is on/off, not momentary.
new house != used HE. If I were you I'd invest in a C8 pro. Lots of expansion potential and I can just imagine what the staff at Hubitat are up to.? Did you get a load of the 2.4.1 release I don't think these dudes take a rest.
I'm waiting for the July 4th holiday to purchase my C8pro, so I'll have time to setup everything. I mean what's another 170.00 when you spent 100's of thousands 
OH WOW!!! ME TOO! Especially the scene where pretty boy puts his hand down the disposal to get something out and the shot up through the opening shows the "blades" and his hand!!!
The anticipation!!!!!!
What happened to FREE ? LOL!
Not trying to pick on you @Sebastien - but I really do take Safety very seriously. I worked in manufacturing for 34 years and have seen my fair share of safety events that were easily preventable. Thus, when I see something I feel strongly about with regard to safety, I feel compelled to point it out.
This is 100% what I would never, ever do. Alexa Hunches could get reenabled by an Amazon update, and the next thing you know your disposal starts running randomly while someone in the household is trying to retrieve their ring that they just dropped out of the disposal. When people drop something down the sink, their first instinct is not to stop and think about disabling the home automation system's ability to control the garbage disposal. They immediately react to try and save the item before it is gone forever. It is human nature.
I would never, ever allow any cloud control over any systems in my home that could cause serious harm to the occupants or the structure. I don't even want local automation control over that type of system/device. For me, the two items that come to mind are garbage disposals and gas fireplaces. Way too much risk, regardless of the reward, IMHO.
With you on that. Murphy's Law is always in play!
TBH, despite having used them for >10 years in 2 houses, I don't entirely trust air-switches. Which is why I have a failsafe that turns off power to the garbage disposal after a set period of time.
I am definitely not comfortable with having a remote start for the disposal. I will pursue the small relay solution so that I can control the one switch, but not the other. I still think it is moronic to have both those switches in the same box. What were they thinking? I have them labeled so I (or anyone else) do not turn on the disposal when I want the sink light.
I know you said it was tile, but you could still make the hole bigger if you really need to. I did my own tile backsplash and ran some down too far over the existing outlets. I used a Dremel with a cutting tool for tile and it zipped right through the glass tiles. I have both a disc and a spindle tool, I think I used a combination of both. Its not a great option, but might be an option if needed.
You also might be able to cut the existing box out of there and replace it with an extra deep "rework" box. Also not an easy task but would help fit the relay in there.
Lastly, depending on the existing wiring, you might be able to put the relay in the fixture box instead of the switch box. I did this on my basement stairs 3-way lights, because of the way it was wired that worked out to be the best place for it.
Some good ideas. I had to dremmel some tile on the backsplash of my old house to fit the Z-wave switch, but that was a small expansion. Messy, and nasty (it was very hard tile). So cutting out enough to expand the box is probably above my pay level. Putting in a deeper box sounds feasible. Maybe. The light is a high-hat, so getting up there is not a fun thing to try, but I would likely have space up there. I really need to open the box and see how messy it is in there.
Just realized, that box is sideways (they all are, in the kitchen) and there is an outlet an inch past it, so no space to expand. Scratch that!
This is what came to mind for me:
