Yup, there is nothing stopping Marco from seeing that Zoro is recovered, leaving King to him so he can help fight Kaido.
The whole Momotaro thing seems to be pretty on the nose at this point. Plus if Yamato has fire attacks, I can 100% see her, Luffy and Marco launching some big fire move at Kaido. Not outside the realm of possibility if the theme is legit.
We'll see in a few chapters. Won't be long now