⚠️*DISCLAIMER*⚠️
I have NOT read the Manga so I don't know as much.
Tashigi, Koby and Helmeppo as the admirals. Tashigi and Coby probably makes sense but Helemppo (eh). The current admirals and vice admirals will be old. Sakazuki, Borasalino, Ryokugyu and Fujitora will most definitely be defeated in the final war. The current vice and rear admirals have no chance in the plot of improving. Tsuru is to old. Garp will never say yes. Gion and Tokikake/the admiral candidates will have their moments but will be replaced by Koby Helmeppo and Tashigi. Smoker has a straight losing streak and is WEAK AS FUCK. Hina is weaker than smoker and is just a little irrelevant. Full-boy or what ever his name is and Jango are just jack offs used for jokes. Bastille weak, Maynard weak, Momonga weak, blablablablablablabla. But the problem is the Fleet admiral. It will maybe be Garp because it doesn't seem like they care or report straight towards the Celestial dragons. They report to the Gorosei/more civilized celestial dragons. But if Koby is then I don't know.