Momonosuke holding up Onigashima.

This theory is all but confirmed now due to the last chapter but Momonosuke will hold Onigashima up for an hour replicating the feat Oden did by holding up his scabbards. On top of this with Orochi setting that fire we’ll get the parallel of Momonosuke holding the island up while it’s on fire as Oden held his scabbards up while he was burning.

Zoro defeating King above the flower capital.

There’s a small portion of the Zoro fanbase that believe in ZKK (Zoro Killing Kaido), but it makes no narrative sense however Zoro defeating King does. I think King will change into his Zoan form and fly away however Zoro will cut him above the capital.

Big Mom leaving Wano betraying Kaido.

I think the fact we haven’t seen the Big Mom Pirates is due to the fact they’re being saved as a way for Big Mom to leave Wano at the right time. This will bring Kaido’s comments of what he said to Kinemon about people leaving when the situation looks bad.

Yamato joining the Strawhats.

At this point does anyone still doubt this? Yamato will leave the island with the crew and it’ll be glorious.

O Tama being a Kurozumi.

Tama being a Kurozumi will be a revelation that’ll end the circle of hatred between the Kozuki clan and Kurozumi clan. Due to Tama’s contribution the old hatred will be let go.

Momonosuke becoming Shogun.

Momonosuke will become Shogun which and fulfill Oden’s dream of opening Wano with the help of Zunesha moving the island.