Yamato isn't available. Yamato's goal was always Kaido. Denjiro is free, why can't he help Inu against Jack?
I mean:
- You can say she isn't until she's literally confronting Kaido. Sanji and Jinbe intended to help against Kaido until they couldn't.
- Denjiro is different because Inu literally told all the scabbards to go ahead. Why would he head backwards to where he was already? It would be entirely reductive for him to go back and help. Plus it's painfully obvious he's going to go help Franky considering his relationship to Sasaki
Again, I say Yamato because she now would have to head back down anyway and Jack is a floor below. It could also be Law, but in this case he intends to head towards Big Mom.
Either Inu wins by himself or one of these 2 does not reach their Yonko destination. It's deductive logic, there is literally no one else around to help fight Jack otherwise, UNLESS someone else quits their fight to assist.