No, BB does not have an elevator, but it's only 3 floors, and they will have someone to help you with your bags if necessary.
If you have a corner Ocean Front room, I think any floor is fine - it isn't any noisier on the ground by the pool (at least not when we were there). They have a "no swimming after 8pm" policy and a guard that circles the grounds, so people can't really "sneak in" and splash around.
Unfortunately, I can't remember the room # set up - since there are 11 rooms on each floor, #1 and #21 are not necessarily on top of each other....If you have a choice though, I would request a south corner room as the construction is taking place on the north side of BB. As I mentioned on an earlier post, we didn't find the construction particulary distracting.
Oh, and if you like pina coladas, try the Mata Colada from the "beach bar" next door at Mata Rocks! mmmmmm - they taste great while you're sipping them in the hammocks