*bounces* Oohh... I know, I know! Absolutely loved it, and surprised I forgot to post, too! Had been even thinking up some of the comments I wanted to type in head, including a lighthearted musing towards the fans (a couple of you, I'm not sure how far caught up, now!) that were watching new ones and old ones and that this Special is great either way, but really loses some context unless you at least have seen Forest of the Dead/Silence in the Library first, to know where River 'started' with the Doctor! Just saying. (and this forewarning is probably belated anyway)
But the Special. I think one of my top favorites, along with last year's! Yes, witty, sentimental, poignant, beautiful... Once it hit me where they were taking us, and getting to see 'that bit' of canon on screen, my eyebrows were raising with bated breath. And before that! Adorably hilarious, seeing the Doctor play along and River so crazy and bad-ass. And yes, like Liberty said, just giving a 'decent ending'. I only wanted to poke River a couple times for thinking the Doctor couldn't possibly care that much for her back. I mean... come on!

And besley! Yay, I can answer those! Ok, so going to have to go on the assumption that you've seen pretty much all the Smith era, then? (for necessary references/spoilers) Because as it was mentioned, River is unusual and partly is who she is because of being conceived in the TARDIS. Shortly after, Amy was caught up unknowingly in the whole evil behind-the-scenes plot to use her baby against the Doctor, and remember when they met the whatchacallit... fake goo people-clones? ("The Almost People"), they had made a clone of Amy (who wasn't pregnant), and taken the real one, so they could take her baby. Then that all came to a head and everything was found out, Amy rescued, Doctor 'went to war' and we had the River reveal.
But Amy told Rory in 'Asylum of the Daleks' that she was upset discovering she couldn't have kids again, because of 'whatever they had done to her' as a result of all that. So River was it.
As far as Souffle Girl goes, we now know all those 'other Clara's' were split-offs of the original Clara Oswin Oswald when she entered Eleven's time-stream in 'The Name of the Doctor'... so maybe there was some memory loss, or tweaks in the names, or she made it up so the Doctor wouldn't completely know it was 'her' yet?