The Kaido fights could potentially give us an enormous hint about who's joining next.
1st wave - Scabbards vs Kaido
2nd wave- Supernovas vs Kaido
3rd wave - Momotaro vs Kaido?
4th wave - Straw hats vs Kaido?
Regarding the 3rd wave, Yamao is already up there. Luffy and Momo are on their way. Marco is likely to be up there very soon too. They're all of similar strength being YC1+ and they all have a relationship with Ace.
This can be like carrying on Ace's promise to fight for Wano.
But ultimately they're not going to be the ones to do the job. I think that's got to be the straw hats. They're the ones who will bring the dawn. The ones who everyone has been waiting centuries for. Whilst some are injured, they're still on the whole in good enough condition to fight again. We'll see another Oars style fight either against BM or Kaido.
If this really does happen, then there's a chance we might see Carrot fighting alongside the crew in this big battle. Looking at the Pedro moment:
1. "Turn yourself into a mighty warrior"
2. "Everyone has their moment"
3. "One day you will understand the true importance of Luffy and his crew's voyage"
4. "Keep moving forward"
When you lay it all out like that, the expected resolution of this build up is for Carrot to have a time to shine in which proving herself a mighty warrior, as she realises the true importance of the straw hats and resolves herself to keep moving forward. Her moving on from getting revenge for Pedro, a thing of the past and instead deciding to help the straw hats in their important mission would be the logical conclusion.
Even more so when we realise that Kaido's defeat will likely coincide with daybreak, the literal dawn arriving and Carrot could then put two and two together to finally fully understand what Pedro meant.
If Yamao stays on to fight after the Momotaro 3rd wave and ends up fighting alongside the straw hats just like Brook did against Oars in TB, then that would be a huge point for her. But what would seem more likely is that she and Marco would go down after they lose, whilst the straw hats would arrive at the top.