Btw the 2 last rewards in the survival tree will mess with any melee build using roid shields since they interact with shield recharge delay and shield regen after kill. Sadly you cannot currently disable any of the rewards...

They are character universal, there is not a max, after you get ca. 13,40% in any stat they only reward 0,10% after that. I dont think there is a max rank i have seen ppl in rank 450 already so...

Do you have to complete the story just once to have guardian ranks unlocked for other characters? I.e. if I complete the story with fl4k, then start a game with zane will guardian ranks be unlocked from the start?

2 questions, 1) is there a max % you can get in a stat? ie, can you only get to 15% in gun damage? Or can you just keep pumping up stats you like, and 2) is there a max level you can get?

Guardian Ranks carry over to your alts. so no worries :)

Are they character universal