Sakura and Gai easily win. First of all:
Sakura>Tsunade, at least in raw ability due to Byakugo giving her a superior boost. (shown with her strength surpassing anything Tsunade has ever done despite Sakura not opening the seal)
Gai>>Ay. Faster than him by far in every category bar Shunshin, which he is still superior in or equal at least. Not to mention Gai has Hirudora, and Ay can't tank it or evade it.
Gai>>>Tsunade for the same reason.
Tbh, regular Gai would solo this fusion. The additions Ay and Tsunade get from each other don't let him become fast enough to blitz Gai nor do they become durable enough to tank Hirudora, nor will they evade it once Gai closes the distance. Giving him the same Byakugo from Sakura only makes this even more unbalanced. Just like 99% of the fusion threads you've made.