Pretty sure he visited Craig in the future.

I thought "Doomsday" was actually pretty good.

Pretty sure they just mean the adult Peter we knew never existed. This episode they almost come right out and say he still existed, but died as a kid.

Remember last season, when the key to opening purgatory was some stuff with HP Lovecraft?

Regarding "died twice" - I think the episode just quietly gave us a lot of information. 
Stuff we already know:

I think it depends more on whether they just use them as the story needs, or treat them as OMG AN OLD ENEMY!

I don't think we're meant to assume Rory and Amy haven't been worthwhile to have around. But at the same time, that's not why the Doctor invited them in the first place, either. He doesn't pick people because he thinks they'll be useful. He takes people along with him because he can't enjoy the universe unless he has…

I wouldn't put too much faith in that casting spoiler though. People throw up stuff like that on IMDB all the time. According to IMDB, "A Christmas Carol" was going to have Tom Baker in it, and also feature Sutekh from "The Pyramids of Mars."

So there have been lots of comments about what the Doctor fears, and what he worships. This might just be me, but I feel like this makes the most narrative sense to leave as a question mark if they are the same thing.

It does seem pretty deathlike, though. It's not just the Doctor's face that changes, it's his whole personality. He really does become a brand new person, who happens to have access to the memories of the old ones.

Actually we do see the number - it's 7 both times. It's definitely Amy's room. (They even confirm that in Confidential.)