I think Luffy and Zoro will vs Akainu and Fujitora respectively, but I doubt Cook will vs an Admiral, especially with the Revos around and glory hogs like Kidd and Killer obviously not just sitting out of the chance to boost their names.
With the amount of similarities Cook and Chaton share, I doubt we miss out on Cook vs Chaton. Also, Cook not getting Adv. CoC + Adv. CoA is suicidal vs top tiers like the Admirals, whereas an Admiral candidate like Chaton is a believable foe he could defeat. Yamato is likely to vs Momousagi, too.
With the amount of similarities Cook and Chaton share, I doubt we miss out on Cook vs Chaton. Also, Cook not getting Adv. CoC + Adv. CoA is suicidal vs top tiers like the Admirals, whereas an Admiral candidate like Chaton is a believable foe he could defeat. Yamato is likely to vs Momousagi, too.
Doubt that those random VA will have any more revelevance in the story than the gifters have in onigashima.
And of course this ideia of Luffy fighting the Fleet admiral, Zoro fighting a admiral and Sanji fighting a random SBS characters make no sense with anyone who have read at last one Arc of the manga, its clear that Oda take the top 3 guys from the villan group and make the monster trio fight them, its just basic Oda writing, dont understand why u guys fight soo much against it lol.
And there's also Kizaru, who i think will be used as hypetool for a certain darkness villain.