When you say steam codes, are you referring to the product registration code? if so, then yes. However, if steam is a separate code from the game itself, then no. The game requires a product registration code that either comes with the retail version of the game, or the down-loadable version of the game. They can only be used once per account/game though.
As far as abyssea/ add-ons. Yes you will still have them, but you will need to re download them from your account once you log in.

At least I think i am right about all of that.