The second cabin doesn't have to be adjoining (can be across the hall or next door) but you have to call. The sleeping arrangement for third/fourth berth can vary by ship and even cabin, but on newer ones (Harmony and on) they are usually sofa/couch pullout. Some Oasis/Allure cabins may have a pullman.
RCL reports the deposits separately in their SEC filings, so I assume it includes all of them. I think everyone who requested deposit refunds for the bankrupt Pullmantur (was part of RCG pre-COVID) got it.
I assume you meant sofa/couch pullout - the pullman is the bed that comes down from the ceiling/wall and usually requires a special key/tool to move/secure.
The cabin steward may leave the sofa/couch pullout, but maybe less likely with a pullman.
You don't need to even play - you download the OBC to the machine, hit cash out and take the payout receipt to the cashier window (or cash out machine).
If something bad enough happens to cause RCI to go bankrupt, folks would have way more pressing issues to worry about than their deposit. BTW, RCL keeps deposits in escrow so they are available for refunds in case of bankruptcy.
In 2014, when RCI planned to roll out Dynamic Dinng to O class, it started renaming the various decks of the MDR as separate venues - deck 3 of the MDR on Oasis ended up with that name and some may still refer to it with that name.
Welcome to CC.
If you do any amount of reading here at CC, you'd realize that, yes, that has been an issue for some time and it has gotten worse since the restart - don't rely on answers from script reading bots at RCI - come here for much more likely to be correct info.