I frequently travel with gentlemen; I'm looking forward to a trip to the French Quarter with a friend very soon, as a matter of fact! (Sooooo jealous of that Dubai offer, Elisabeth! Wow!!)
To answer your first question, never assume anything. It's best to lay it all out there when setting something like this up. Every lady is different, some would go just for the trip to Hawaii, some wouldn't. Some might want to work, some might not. Most ladies want their own room, and some gentlemen want the provider to stay with them. You gotta talk about these things. It can feel a little awkward to have these kinds of conversations, especially if there is a friendship there, but it is absolutely necessary!
Expect to compensate for BCD time....make sure you have done at least one overnight...and give us some space on the trip. As long as everyone communicates their desires and expectations upfront, it can really be a great time. Have fun!