The admirals are basically the WG Yonko. I don't see them stopping any Yonko after what Luffy did to Kizaru, granted he was somewhat emotionally compromised, he did have moments of seriously trying to beat Luffy. Especially with Saturn.
I think the Admirals will end up fighting against Yonko in the war but getting tied up with first mates, especially for Luffy.
I am most interested in who Dragon will end up fighting. Sakazuki is pretty fitting, especially since it has been revealed that Dragon was a Marine, he must have some history with Sakazuki... but by the same token so does Luffy, Luffy needs a win over him.
How the hell is Oda going to write this war!?! There are so many moving parts!
I know he is going to pull it off, and it will be the biggest war in Manga/Anime history.
Bigquestion is: Will it be a one day war? Like Marineford, where the majority of the hot combat takes place over a few hours.
It's actually a really interesting question because Shonen Jump has a few data points when it comes to an internal sense of how to depict a war. My Hero Academia, for instance, couldn't do a multiple day hot war, BUT was able to do multiple locations around Japan. Oda will definitely set a standard that editors are going to be referring to when they assist the next generation of authors.
For Oda, I think he's been practicing how to depict large scale battles in preparation for the last war.
In Marineford, we had the war that actually severely affected the style of upcoming large scale fights. In this war, we saw many small bouts, but not anything like Zoro VS King, for example. Call those the 'clashes.'
These clashes saw characters well, clashing, and then parting, to go elsewhere in the fight.
Move to Dressrosa. Dressrosa largely did the same. Oda juggled many new characters at once, but this time, we had a return to traditional match ups with conclusive endings. Entirely new characters got those title fights however.
Move to Whole Cake, and we return to small clashes most of the time, with attacks being exchanged as the strawhats try to escape, and their allies execute attacks here and there. Here, you have the main fight of Luffy VS Karakuri going on in the background, and it is a long fight, complete with a break for Kara.
Then... Wano. Once the invasion of Onigashima happens, we see many exchanges throughout, before Oda finally settles into the traditional match-ups. Worth noting, the fully fleshed out fights went primarily to the strawhats plus Supernova.
Oda has a significant advantage over his author friends in that he now has the most experience out of ANY shonen jump author when it comes to large scale conflicts with many players/factions and many battle speeds. Him having the most data due to his own efforts also should give him a better sense of what he himself is capable of.
Looking at his trends then, what I think is almost guranteed is that we're going to see insanely creative clashes throughout the first leg of the final war. Things like Franky crashing a motorcycle into Big Mom's face, Sanji taking a hit from King and walking it off, Chopper slapping Queen, Crocodile trying to swipe at Whitebeard, Ivankov threatening Kuma--these are the kinds of moments that the clashes will bring forward.
And then, it'll be like Wano where it winds down with the traditional matchups.
Unknown factors are:
Will Luffy be a fight that happens through out in the background, like with Kaido? I hope not.
Will stuff like Fishman Island be settled or will that plot unfold at the same time as the war?
If this war takes place on multiple places around the world and not one fixed location, then we are looking at a relatively risky proposition, when it comes to managing the timing of events. Doing multiple different locations around the world will definitely give heavier weight to "How the hell is Oda going to write this war!?!"
