Plus why would they mean only one can be a former divas and womens champion?
Like you I think four out of the six are Fox, Bellas and Trish, I just can't think of who would be the last two what with all of the people they confirmed weren't in.
Lita and Kharma maybe? That may just be wishful thinking, but there aren't many other options out there. I suppose Vickie could possibly have a Michael Cole-esque dual role as both a manager and wrestler, seeing as how she has competed numerous times over the past few years. More than Cole anyway.