1. Not that I'm aware of.
2. That's actually kind of funny, and should probably be errata'ed. I'd just allow the use of Flowing Water strike, but if you can't remove your Immobilized condition with an opp, it auto-fails (the main effect doesn't trigger regardless of successes).
3. a. Resist rolls, for one. Not sure if there are any others.
b. Yes, as I understand it, it works basically like that, which also seemed odd to me when I reasoned out the same thing. That said, it only triggers on a resist roll, and if you have to make a resist roll while Incapacitated, you have other issues.