I'm about to find out if I can convert coil to solo air on the 2012 Boxxer RC tomorrow. Got the 2 parts I needed. Just need to go pick up my new bike tomorrow and I'll be starting the process.
Very much so possible to convert the coil to air. Works great for me since i'm a lightweight rider. And I don't see why you couldn't convert the damper side to the R2C2.
If you are trying to convert coil to air, and have already ridden the fork on the coil, the air spring may not seal properly against the inside of the stanchion due to spring scratches. This came from Shawn Cruickshanks directly, so I know it's good info. The proper way to do it is with a new stanchion, or convert the fork before riding it.