To be honest, Tsubaki is still not ready for debut, and until they are I don't see them adding a new group. Perhaps they might add some more members to Tsubaki in hopes that it strengthens them. They haven't debuted yet, so I don't see why not.
Also I'm expecting a MM audition sometime soon, but only if they add 1-2 members only since the group is large as it is. I kind of feel that now that Riho is gone, there is space for Ruru to join. Ruru and Kaede are the types that will become the ace of their group when they finally debut. I feel like that holds them back from debuting earlier, but the pay off is always great. (Ex: Karin)
When C-ute graduates I can see them still being active within UF. They are probably just waiting for the right timing. With Riho and Kanon graduating, you don't want to graduate an entire group.