Well, even though my expertise is in rare and exotic Omega Jackalope watches, I'm going to take a crack at this, and Steve or Chuck can do the Benny Hill "whap whap whap" on the old bald guy's head (that's me) if I get it wrong.
The movement in the 2293 Ti Seamaster is 3301, and that IS the base movement that had the coax added into it for the Planet Ocean. Fact #1 I do NOT know is whether adding the coax movement changed its external dimensions. If it didn't, you might be able to pull off a movement swap.
Problem is, there is a supposed reliability issue with the chronograph part of all 33XX watches, so apart from getting the coax into a 2293 case, I'm not sure what you're accomplishing. Maybe you get a little more accuracy or slightly longer time between service, but those are going to be minimal gains even if they pan out.
More importantly, you will be creating a real, live Frankenwatch with ZERO resale value, and that's one HELL of a high price to pay simply to get a coax movement in a Ti case.
As far as the black bezel on the Ti case, forget it. The black bezel is SS, and the case is Ti. Add some seawater, and you have what is known as a battery. One of those metals has a greater half cell potential than the other one, and that metal will start to lose atoms to the one with the lower potential. Yes, both metals are corrosion resistant, but they're not immune to galvanic corrosion if they're very close to each other.
