So i brought Boone with me to the legion camp and we destroyed everyone so far but, last night i was at the top of the camp and a myriad of them attack and bombard us. My question is, can i still complete the quest if i choose to attack the legion?

Can you complete which quest?
You can't befriend Caesar/Legion do Caesar-given specific quests if you kill/attack the Legion, certainly...but it shouldn't break the "main quest" if you're not playing/supporting Legion to begin with. I take Boone with me all time, because we like to kill Legion and I don't pander to both sides just to see what the other side has to say.

I can see you're not siding with the Legion.

There will be quests you fail and can't complete. But you can always finish the MQ with Yes Man.


B)

I like how Arcade yapped at me and tried to walk away when I sided with the Legion and went to Legate's Camp to plan the attack on the dam.

Needless to say, I had to kill Arcade for his disobedience.