RadioRA2 or Caseta for condo automation ?

I am very much interested in RadioRA2 system so I could automate my apartment lighting, as well as integrate into various systems I have... however, it looks like Caseta might be more compatible with various systems... so need some help deciding which system to get, and IF I could use RadioRA2 keypads/dimmers on Caseta system as I like their looks and function WAY BETTER!

Here are my needs:
- 2 Keypads (one at entry, one in living room) to control lights all on/off, plus mood settings
- 4 Dimmers, 3 magnetic, 1 electronic transformer control
- 2-3 plug-in controls (table lamps, etc...)
- 4 on/off switches
- 2 roller shaded (future setup)
- Integrate into Nest
- Control Sonos
- Control by Harmony Remote (integrate to home audio)
- Potentially integrate into SmartThings
- Integrate into HomeKit
- ALL controlled via ONE APP [iPad]
- Give me conditional programming --> unrelated to RA2, but I want a system that could do this

Now, problem with RA2 seems to be, that it cannot be controlled by Harmony, or SmartThings, and that it's more of a complex setup than Caseta that has even more capabilities.

Questions:
- Can I somehow use Harmony Remote for RA2?
- Is there SmartThings integration in RA2?
- Could any of the RA2 keypads be used with Caseta?
- Could RA2 dimmers be used with Caseta?
- Is it even worth the extra investment to go with RA2 for such a small setup?

Thanks

No, you can't use RadioRa2 dimmers/switches/keypads with Caseta. And yes, I would agree that for a small sytem Caseta is the better way to go. There are ways to use a Harmony, but not SmartThings (as yet - perhaps it's coming - Lutron has tended to roll things out to Caseta first, but my gut is that SmartThings is unlikely to come to RadioRa2).