6.) I ordered replacement heads and was asked if I wanted 1.8 or 2.2 - I got 2.2 - not sure why, but did I screw up for my eGo-C upgrade batteries??
You should be fine with the 2.2 replacement heads.
Keep the old ones around until you have time and inclination to get into all this dry burning, rebuilding stuff. It sounds overwhelming at first, but once you watch some of youtube vids it all starts to come together and make sense. Lots of people would take them off your hands to rebuild if you decide against mucking around with them at all.