Shouldnt Mihawk be in that same arc as the two of them or where do you see Mihawk's defeat?
During WG war or post-WG war?
WG War will include everyone imo
But Mihawk, Shanks & Blackbeard will Survive it (BB Might still get Defeated somehow though cuz He will return Stronger anyway)
And They return for Post-WG Arc
Notice how Oda is creating so many Treasures to find & Objectives instead of making One Piece the only Goal
This clearly shows that WG War is a Massive Battle Royale (Oda did call it that) and obviously SHs aren't gonna Win everything
So there are gonna be Multiple Winners & Losers
I can't really predict Oda's Timeline, there are too many Factors for me to bother doing that
But imo, Final Battle will officially Start when Luffy meets Shanks, just like Thriller Bark Officially Started with Luffy meeting Brook
After that happens, then it will be easy for us to determine when Zoro & Mihawk will Fight
Cuz there will only be the Final Two Villains left to Defeat