I don’t see them getting a new captain but I did think it’d be funny if it did happen with Big Mom and Kaido, that if Katakuri and Yamato took over Luffy would essentially have four Yonko crews on his side, I’m including whitebeard pirates as well as Shanks

In case you didn't know, Old Man Newgate is dead. Teach is the new yonko. So, no. Not 4, maybe 3.

Are you including the beast pirates in that statement? because i doubt that yamato will take over that crew. (After they beat kaido)

If they beat kaido

Kaido would most likely fall.

The strongest creature In the world beaten how? Please tell me. A raid party would do nothing luffy and his allies are all weak compared to kaido. Then you've got king and queen who could beat luffy. I dont see kaido falling m8 its just gotten to a point where he is described to be the most powerful and nothing will change that. Luffy didnt beat big mom last arc he ran away and as a consequence Pedro died (his choice ik) but if he stood a chance it wouldn't have gone down like that. In all the arcs luffy never loses a frjend unless the situation ends in retreat. Impel down, marineford, saboady without kuma being a mole would have seen all the straw hats getting annihilated.

The reason Luffy didn't stood a chance against Big Mom was that he couldn't get past her defence, same with Kaido. But with his advanced armament haki, he can ignore defences. Now he can deal damage to both of them. And I'm aware there is a power gap between him and Kaido, but why would other Supernovas would be there if they wouldn't fight with Kaido? And by the way, the reason Luffy couldn't fight against Queen was the fact that he couldn't jump around without losing his head. And considering that he is in his best when agile, being stuck in a ring reduces his fighting capability. If they fought now? Luffy would win.

Your first point.

1.luffy can "ignore defence" with improved armament haki.

This is not true, the advanced version that he has acquired will ignore a portion of defence but it really depends on how strong the enemies haki is at taking that blow.

2. The point of the supernovas being there is to assist in the fight against kaido.

The uniqueness of one piece is how good the world building is, this is done in many ways but its a moving story, many different stories operate in the background. The supernovas were there for there own respective reasons, reasons that are believable.

3. Luffy can beat Queen or King.

This clears that up, and unless your telling me he can use gear 5 or something to beat queen; he wasn't even paying attention, let alone serious.

It’s a possibility they can or will beat kaidos but he is the strongest creature in the world so on the other hand there is that. So it’s a 50/50 on where this arc will go but this arc is the last for the four emperors saga right? And it’s gonna be a war too, so we don’t know what will happen but you guys have awesome evidence!

I assume Perospero just because i think Katakuri would get a bid demotion after losing to Luffy just like the other commander did after losing to Urogue