You can promote any pawn to a queen.  It doesn't have to be a pawn on the queen's file.  In fact, it's possible to have nine queens at the same time, by promoting all your pawns to queens.

You can indeed castle after you've been checked.
You lost your right to castle premantently if you've moved your king or that rook.
You can temporarily NOT castle if you are currently in check. 
You can temporarily NOT castle if your king will pass over a square attacked by an enemy piece.

No rules have been changed.  I'm not sure what you are talking about when you are talking about the "old rules."

I've never heard of the rules the OP has mentioned, but the rules of chess have changed. They weren't always the way they are now.

I've never heard of the mentioned rule; only thing even close is that promoting pieces became much more important when the queen was strengthened.

There is also a history of regional variants.

Yes, but not regarding queening only "queen" pawns and castling after one has been checked, which is what I was referring to.  Also, I don't believe he's asking about rules that are 300+ years old.