Many of the characters you listed are characters I had hoped to never see again, so I dearly hope not. Aside from that, I really doubt they'd be adding any content to the original Dissidia, but I don't really know anything about a sequel. If anything, they would add in characters like Ramza, Ajora, Lightning, etc.

While on that note, if they were to ever bring in Ramza, do you think they'd have Ajora as his opposite or Delita?