River may not have known the circumstances surrounding his death, as The Silence could have erased it from her memory.That's right. If you recall, the River that was invited to the beach along with Amy and Rory was already locked up in the Stormcage for murder. So why River on the beach doesn't recognise the circumstances surrounding the murder and seems to be genuinely surprised by it all is something that is yet to be answered.
Just after The Doctor dies she shoots at the Astronaut and nothing happens. She says something like "no, of course not". It's very possible that River knows she killed The Doctor and was doing time for it, but never knew the circumstances surrounding it, such as when, where or how.
So she knows she kills him, but it wasn't until she witnessed it that everything came together.
The Doctor knows the circumstances surrounding his death (maybe not all of it, but enough) so he knows that Amy, Rory and River were there when it happened (not sure about Canton). As a result he knows that he needs to invite them again or else he'll be changing his own past and future which could be catastrophic.- Why would the 1103 doctor choose to contact the Rory and Amy from BEFORE he left them for 200 years?
Yes. The version of River of who kills the The Doctor is still early in her regeneration, so barring any unexpected adventures she'll have been studying at Luna University for a few years in order to earn her doctorate. So none of the other episodes she's appeared in has happened for her yet, with the killing of The Doctor being much later in her life (but before Ten meets her).If it's River in the Space Suit the kills him, and she is in prison for killing him, then the version of her that goes to Utah/1969 is a version from after those events?