River Song is a character created by Moffat though, he wrote the story in that Library with her in the Tennant era.
As for the cot name guys, could the name not just be "The Doctor"? She is Doctor River Song after all.
That episode blew my mind. So many thoughts and ideas about it. It also explains why she was a bit awkward/in awe with Rory when she met him at the start of the episode as that would be her dad technically.
One thing I thought they missed out on though was if the doctor was building an army of supporters, where was Captain Jack? An invincible man would probably be quite useful in an army, no?
Why would he use up all his debts when he only needed as many as he had?