You're right, some of them disappeared. Mariah was quite the pumper, saw someone say she wasn't even real on another board. Whether she is or isn't, she went from 100 to 0 on all boards, so I think it's fair to say she is probably no longer in FITX.

One of the mods that was removed is actually more active on another board, one of them clearly was inactive all together after a couple months modding, likely are no longer in FITX. I think some people have migrated, PM me if you want more information.