Liz,
I would go for it also. It is hard to find someone who wants to travel and dive as much as I do. I think the "list" should also include the diver’s experience, in addition to smoker, party-ier, and what their goals for the trip are (5-6 dives a day or maybe a dive every other day). I’ve been to Bonaire 5 times (last time was in January staying with you). In addition, I’ve gone to other dive destinations with groups, and livaboard; along with cruising prior to scuba diving - all having someone unknown assigned as my roommate. That worked out fine in all cases, but it worked out even better when I found out who it was going to be and could email or chat about our likes/dislikes and goal for the trip ahead of time.
For me, the additional concern in places like Bonaire when traveling alone are that likely your "cabin mate" is also you dive buddy. I am much more particular with my dive buddy than I am with a cabin/room mate. All the trips prior to the one last January were with a dive club. While I had never met my roommate before, I knew there would be several other divers that such that I could probably find one with similar dive skills and abilities, and I usually did.
As far as taking your equipment, where are they going to go? You are on a small island, and are probably sharing the truck. I can’t imagine how they are going to put your BC/Mask, Regs, or such in their back pocket and sneek them home.