I built my house 3 years ago and got into SmartThings a year and a half ago or so. Hindsight is 20/20…there are a bunch of things I would done differently not only with home automation but just the house in general (better outlet placement, more outlets, extra circuits run to things like the garage, Ethernet throughout the house, etc). But as far as HA goes I would have put hardwired sensors on everything (doors, windows, etc) I could and brought them all in using ST_anything ([RELEASE] ST_Anything v2.9 - Arduino/ESP8266/ESP32 to ST via ThingShield, Ethernet, or WiFi). All my lights would be on GE dimmers, all the ceiling fans would be GE 3 speed fan switches, the lights I didn’t “care” about would be Leviton paddles that match the GE’s nicely. I’d probably get Aeotec for motion because the “new” SmartThing ones arn’t very good (the old ones which I still have some of are great). I’d also hardwire security cams, ones that run on PoE (like Lorex or similar) so I could just run Cat 6 Ethernet to their locations.
As far as lights themselves are concerned I’ve been pretty happy with the Cree 65w 6" retrofit downlights. Also using the Phillips 40 and 60w “warm glow” candelabra bulbs in all my ceiling fans. Not as happy with those…with the GE dimmers they sometimes don’t turn on. Or more specifically they turn on and instantly off even though the GE switch is on. I blame the switch more but I don’t ahve the issue with the Cree bulbs and the same switch. I think it has something to do with the older GE dimmers slowly ramping up the lights from 0% to the last known value. The new Z-Wave Plus GE dimmers when switched on go straight to the output without ramping up so I’m going to try a couple of those and if the problem goes away (I think it will) I’ll put those in for my ceiling fan lights and move those switches to others I haven’t replaced yet. If the problem still happens I’ll switch out the Phillips bulbs for something else. Just a little harder to find the small candelabra bases.
If you have the ability see if they will do a multi-zone HVAC system with proper balancing/bypass damper. The Keen vents are a neat idea but restricting air flow from your furnace can/will kill it after a while. A standard furnace is meant to blow xxx CFM of air and restricting it can burn up the motor, burn up your heater core, or both. The Keen’s are supposed to have a pressure override to prevent that but a properly configured multi-zone HVAC system will be a lot more efficient then restricting at the vents. But that also means it probably won’t be on your HA system since it would have it’s own controller. But still…having a system designed to be able to properly heat/cool one floor independently of the other floor will always be better then one that heats/cools both but restricts air flow at the vents.