Meh Metaknight looks like a Marth replacement especially when he does that half moon sword swipe above Link in Pic 1. I'm not sure about Samus but it looks alot like she's doing Sheik's forward tilt. That can be seen in the SSBB trailer. Possibly a Zelda/Sheik replacement?
The pics sure are cool. I can't wait for SSBB to finally come out on the Wii.