Didn't they confirm Fedor signed a contract extension or something? Anyway, Overeem looks like he has some of the best striking in heavyweight mma, certainly as good as the UFC's heavies. He also has decent submission skills.
His wrestling isn't up to the standard of guys like Brock and Cain but he has more experience. So I think he would very likely be able to beat some of those guys.
As for Fedor vs Overeem, I believe Overeem has a small advantage in striking, but fedor can knock a guy out at any time. Fedor is at a size and strength disadvantage but seems faster and he has the edge on the ground so it would be an itneresting match up. I'm not sure who would win but I'm hoping for Fedor. I think Fedor is underated right now. Peopel say he hasn't fought any serious heavyies but the UFC doesn't have the only good, tough fighters. Time will tell where he really stands. It doesn't look like he'll ever go into the UFC so the only chance is for some UFC fighters to jump over to his side of things.God knows if that'll ever happen.
Member of DaJoGen MMA school under Dave Hagen and Team Chaos fight team under Denver Mangiyatan and Chris Toquero, ran out of Zanshin Martial Arts in Salem Oregon: http://www.zanshinarts.org/Home.aspx