Interesting. We know Karen is returning next season so something happens with her, but we haven't heard anything about Arthur Darvil. I really hope he does return because I've liked him all season, even if he's a mellow, passive version of Mickey. However, I would be very interested in seeing him as a companion next as a human consciousness (or whatever has happened which will be revealed in "The Big Bang") in an Auton body.
I liked Rory too. Auton Rory seems very much like the real Rory, which makes sense since they obtained him from Amy's memories. And judging from the clip they released yesterday, Rory's personality seems to have won out over his programming. But would Amy settle for what is essentially a plastic clone of her fiance? She couldn't marry and have children with him now, which is what she wanted eventually.
River is his mother.
She says something like "I should have never let him out" towards the end of Pandorica Opens.
I don't think she's is mother. She calls him "my love" (assuming she was talking to him; I think she was). And in "Forest of the Dead" the way she responds to his question about why she has handcuffs, well, she definitely wasn't talking to him as if he was her child.
Going on the leak photos, we see the Pandorica, we see [young] Amy, and we see A 11th Doctor.
There's also a picture of young Amy standing in front of an opening Pandorica, which makes me think he really is trapped in there for almost 2000 years. I hope he's in some kind of suspension, otherwise he'd go insane.
My theory: The Doctor uses the Pandorica + Stonehenge to send out a psychic SOS to Amy, a warning, meant to get her to stop him from being trapped in the Pandorica in the first place.
How would Amy be able to stop him though? He wouldn't listen to her; he wouldn't even listen to River when she begged him to run.