bee buffs jinchuriki and gives x2 atk mei gives field that buffs water and fire, aoe damage etc etc ...they are 2 different ninjas that do diferent jobs and for bee's mood if you want higher bp go for atk (thats bad imo because you don't use him to do damage,i personaly prefer resistence for the shields at the start but you c*e ninjutsu for higher regen i guess,in 3 tries each i got more damage with resistence mood was kinda surprised but meh yolo..

in that comp mei would buff only the main herself and iruka leaving naruto out,if you use bee he will buff only naruto