My kid wanted a bottom bunk so I am with @Hanna on this one - don’t assume your first choice is everyone else’s.
And here’s another idea – the closets may not all be the same. Desk locations might vary. If there are 3 things which are different, each of you gets first choice on one, second on another and third on the last.
DS’ roommate who picked the big closet got the bed nobody wanted and second choice desk. The kid who chose the loft got the desk in the corner and second choice closet. And DS got the desk with the sunlight bUT the closet near the door with 2nd choice bed. They all felt it was fair and that they could live with it for the year.