If you want to get money, wil, make use of a small “bug” in the game, where if you quicksave then load, you’ll fight certain enemies on each map floor. The most notable is the one where if you quicksave on the final map floor before X-Death, the second - not first - fight you encounter are Movers, who drop about… I believe it was 199,999 GP, combined?
About the dungeon: Most of the bosses in there are required to beat it, yes. The only oens that are optional are Omega Mark 2, and Neo Shinryu, which I didn’t bother with. There are several save spots inside the dungeon, although they’re a bit few and far between. Anyway, the treasures inside are very, very nice. I have a lot of them equipped every chance I get.

