1) no idea
2) started with Oculus Rift CV1, now using HP Reverb 1. No issues between ED and either of these. Setup of HP Reverb was a bit bumpy (installation of SteamVR, then switch to beta branch), I can't remember if the Rift installation was any less bumpy, though (as I was not using the Oculus store version of ED).
Had more issues with the Rift and its tracking cameras than now with the Reverb - but in either cases an occasional reboot of the PC is necessary. Right now (i.e. before today - I got a new Windows update today), my Reverb setup had more crashes than my Rift setup - but that may also be due to the overall system, I probably should update my motherboard BIOS and its drivers one of these days (Asus B550, after installation I also had problems with audio drivers occasionally grabbing up to 50% CPU...).
Visually, the Reverb is miles ahead of the Rift - but I guess you knew that already. A hefty GPU is needed - I'm (now) running a Ryzen 7 3800 with a GTX1080ti, watercooled, and the GPU is struggling to keep up the FPS, especially in multiplayer PvP scenarios - visiting the Ghost Ship in open was not a pleasure. Since I don't care too much about PvP (and none at all about unvoluntary PvP), switching to PG/solo usually fixes that. I'm waiting for reviews and benchmarks for the AMD 6800 vs. RTX 3080 (and waterblocks for the 6800...) before deciding what to uprgade to.