Id imagine if they had any bonus to those who participated in the beta, itd come from saved game data, or data that is saved in the cloud. So I think deleting the beta is fine.
FF XIV had a beta on PS3. I deleted the beta but kept the game data and my character carried over.
Dont think TF has anything like that, but just in case, I think all youd need is game data/saved data.
MGS is garbage now? I agree the story is convoluted and the cut scenes are too much... but the gameplay is really unmatched in the genre.