The fact that you think tsunade can beat k11 by her self is ludicrous. Neji or hinata can shut down her strength of 100 by themselves, let alone together. Sakura is pretty much a carbon copy of her at this point, and shino or choji solo's her slug. That still leaves 6 ppl on the team unaccounted for that can do anything between covering fire or straight up 1 shotting her. Plz don't make me go into detail about this. It won't end good.
Even in scenario 3 mei doesn't have the tanking or speed feats to dodge or tank the likes of Lee(reverse lotus),or kiba(fang wolf fang, fang chasing fang) and a restricted tsunade isn't gonna find the time to heal her with two gentle fist users on her ass, sai raining death from above, shikamaru's shadows, katsuyu spitting acid at her own master etc etc.
Like I said rank is not a clear indicator of power. Kakashi is jonin yet he can take on kage, same for guy.
Part 1 garra was stronger than most of not all jonin shown in part 1.
Naruto is genin yet he solo's kage.
U see my point?