I think I may now have some space on deck one available for it with the gangway/stairs and lift moved off to either side of the passageway.
You know, IDK if this could/would apply here, but a lounge of that size could indeed be quite small. If we're going with a ship with only 2 or so decks, I might adopt a small space similar to the small lounge on the upper level of a 747, with a small spiral staircase leading down to the bottom deck, to save space.
Again, IDK if this applies... I'm just thinking out aloud.