look... the teams CAN do it. the real question is about the knowledge and modding of the players using them.
one player using zylo p1 + Zinn + Princess Zody + CLS and thrawn p3 with good squad under it can solo the whole HAAT. one player.
you have multiple teams like that, and you still may not be able to.
i would suggest you to look at videos of those teams and tactics how to finish those phases, NOT FROM THE GAME PROMOTERS like anhald, warrior, mcmole... by "normal" people who just uploaded their fights to youtube. see their mods,and plan according to it.
you maybe need some practice also, so it might be that you fail on the first try but on the second/third you can pass it without even investing anything else in your teams.
Good luck.