ok used to play FO3 all the time, fantastic game, did so many things that FONV fell short of but both great games. i decided to replay thru FO3 again and its been a hot min, the question is..After u beat the vanilla game, then wake up for Broken Steel, can u still do all the quests that u didnt do before hand, like the lil sidequests like antmisbehaving etc? also do the bobbleheads and unique weapons still obtainable?

Yes.

Broken steel does no changes to the game. It only adds things to the game.

sweet tyvm =]