Why not room with a stranger? I have yet to be on a dive trip where I knew my roommate beforehand. There have been zero problems. A little courtesy goes a long ways and most divers I know are pretty courteous.
Heck there is a web site devoted to single divers, and no it is not a hookup/dating site. It is for divers without buddies but non-divers are welcome also. They arrange several trips a year. No reason DiveBuddy can’t do the same.
What would I like to know?
Night owl or early bird?
Smoker? (outside of room only)
Photographer? If they are going to be my dive buddy also.
Hard core diver or strictly recreational laid back diver?
Snoring level in decibels? Should I bring ear plugs?