None of the other Castle cast members besides Fillion have been given an indication about their future on the show though sources indicate that Seamus Dever and Jon Huertas would likely return alongside Fillion who is said to be close with them while not getting along so well with Katic.
Aaaaand this show is officially over. I'm kinda glad I stopped watching after S5 finale tbh. Shame because up to that point it was a brilliant TV show, arguably one of the best on air.
that show is doomed!
worst! decision! ever!