Good to see you thinking about this, here are my responses:
1) The kayak thing: inflate the wing, toss it in the water and put it on. Everyone seems to think getting in/out of the harness is a difficult endevour, but with a little practice it becomes fairly easy (unless you, uh, forget to disconnect your drysuit hose).
2) Surf. I'm speaking as someone that has spent a lot of time riding waves, on boards, on my belly, sometimes inside them with a board washing around . . . I don't see how a jacket BC is going to keep your head up. You mention "riding" waves in, I do that belly-down, with my head back and up. If I am in scuba gear, I'd have my reg in my mouth. If I really, really, wanted to ride a wave in scuba gear, I'd want to be as streamlined as possible. So, I just don't see how a regular BC would be better here-unless you are thinking of it as a life preserver that keeps your head upright (which neither a BC or a BP/W really should be relied upon to do).
3) You mention rocky exits as well. If you are going to need padding on the off chance of getting pounded on rocks getting out in surf (something I also have experience with) I think you'd need more than what a regular BC can offer. Padding necessarily equals buoyancy as well . . . so if you have a padded BC that would really protect you from rocks, you'd also have a ton of extra weight on you. Extra weight makes it more likely you are gonna slip . . . maybe a football helmet would be a good idea as well. I'll take my chances with the occasional rocky exit in exchange for a system that works well where it is supposed to, under water. Careful observation and planning should get you out of the water okay.
Good questions, these are my two cents.