I have a curious question as to how the faction leves work, espicially the new ones. I have never done factions leves but with the new coliseum gear and me being a collector I wanted to try and farm them, in case they are also removed.

I know that you have to do them in order to unlock them, but once you finish one, as in 2~4, does it stay unlocked?

Or if you plan to say farm the 4th quest per say, do you have to start back over at #1 and work your way back up unlocking them and same for 2~3, always doing the ones before each try?