First, pack the BC. It will be simpler all the way around. If you have to remove your air2 that is an easy process and you can pack that with your reg for carry on, if you feel it's worth the effort.
That said, if you decide to carry-on the BC, don't worry about it getting damaged in the overhead. These things aren't exactly fragile and they're designed for "rugged" use. Especially the jacket style BCs that are over-engineered with redundant seams, and very rugged materials. Throw it around stack stuff on top of it, and let it ride. Inspect it before you dive. The only parts you have to worry about are the plastic parts and if it's relatively new there's not even a lot of worry there. Don't drop weights directly on the plastic parts and you should be good.
For what it's worth, I've always just packed all my gear in my checked bag. The last time I flew, though, my luggage was delayed because my flight was cancelled and I caught a flight into Miami instead of FLL... My first night there I dove on rental gear, no biggee. Not my preference, but it was perfectly acceptable gear. Internationally I might be more concerned but Roatan is well stocked with dive ops, from what I understand so I still wouldn't worry much about it.