I'm about to embark on my Hubitat journey but before taking the plunge, just wanted to check if it can actually work well with multiple members in the household. You know, the type of activities like, if my and my wife's phone is away from home, then turn the heating to away. I've read these things are possible but is it extremely complex or as easy as installing an app on HE and all the phones? Or is this something I will need to invest significant time into.
Also, as far as I understand, HE would allow me to make a lot more customised use of SMART devices. So, I could use my Hue sensors to trigger non-Hue activities (and not just my lights), or will I still be restricted to using them through the Hue bridge and have the same restrictions?
This is definitely possible. You will need to install an app just as @jwetzel1492's Combined Presence:
Complexity is a relative term; it will not take much time at all to get it installed. But it will take some time investment to tweak it to work exactly as you desire. The length of time depends on several factors, including the make/model of phones, the cell carrier and GPS availability.
I don't have Hue sensors. However, the last I heard, Hue sensors paired to the Hue bridge were not "seen" by Hubitat. If you pair Hue sensors to Hubitat, they can be used to control Hue and non-Hue devices paired to Hubitat.
I have Hue sensors on my Hue Bridges because I set them up first and Hue does what I need to do in regard to switch on lights at sunset, dimming at certain times etc. I also have Hue sensors on Hubitat, these are the ones I use for Light automation (back to the Hue bridge) but also wanted to use the temp sensors in them etc. So basically, Hue sensors on the hue bridge cannot be seen via HE but Hue sensors on HE can be used to control hue lights and HE devices.