So, former Warlord bounties:
That leaves Doffy, Hancock, Kuma & Moria. I can't imagine any of the first three getting bounties lower than 1.5B. Hell, I'd bet on 2B+ for them based on Croc. And Moria was said to clash on par with Kaido in his prime.
It seems the writing on the wall about Warlords is pretty much the exact opposite of what many people have been saying for years. There's seemingly no "skill cap" on how strong a Warlord can be--as demonstrated by Mihawk-- and I'd bet you have to be at least as strong as the average YC to maintain your position.
EDIT: I forgot Weevil, but I'm sure he'll get a high-ass bounty as well