What characters are definitely leaving after season 3 and which ones are coming back (whether it be as regulars or just recurring characters)

Where did you read that Kevin was staying? I can't find it anywhere

I forgot who it was, maybe Ian?, but they said all the juniors (Tina, Artie and Blaine) were definitely staying.

Insteresting I think at the beginning of the season they changed some of them to juniors to keep the orginal cast. And I can't see Mike leaving without Tina and I don't know about Kurt leaving without Blaine. And if Naya staying I think Brittany will get held back as Santana will still be around. It's good to know that their sticking around for season 4 but I'm prepared to be flooded with new characters.

that will be sad if mark is leaving i mean i am thinking it will be that way but he is my favorite male character

Naya comfired she was staying via Twitter ;)

Yay thank goodness! I luv Naya ^^^ <3