Kate, I bet they would do two cabins for two singles - Ellie is the GM and she's great. It would probably depend on how booked they were.
I never felt unsafe for a second. But if you are very clear about fitness, things that might be bothersome, your pilot/guide can work with that ( Paul, the owner and chief pilot, seems to do a really good job of matching guests with guides - and I visited with several of the pilots and liked each of them a lot).