The small comedy club, the rest are not really required, and you are likely to get in without one. The aqua theater and production shows usually can be booked the month before sailing.
Weekly? Over the past two months? Some have reported having to create a new account to fix the issue - perhaps suggest that to them if you are not getting anywhere.
Not only are the chances of any other same category cabin being available extremely low (O class ships are likely sailing well over 100% capacity), but it's also very unlikely they'll allow it anyway.
I don't recall any report of anyone ever receiving notification of a cabin assignment - you might get it indirectly if you bid Royal Up and your bid gets cancelled.