1. I've always assumed that the bearings in the higher quality Shimano BBs are better, but functionally they all seem to work the same and are compatible.

2. The bottom bracket type on both frames looks to be the same, so using the FSA on the Cannondale should be no problem, you just need the tools to remove and re-install everything.

3. To go 10 speed, you are correct that you would need to change the cassette, chain, and right-hand shifter. The crankset might still work with the 8-speed stuff, although the chain will probably rub on the outer ring more than it currently does when in the small-small combinations.