The thing about replacing Kizaru doesn't matter much, I don't think something like that gets decided upon on a matter of days, especially if they do stuff like worldwide drafts.
Either the marines simply don't have enough time to replace Kizaru before the story ends, or we get a new admiral (officially the weakest) for a replacement.
Not a big deal either way. There's no reason why the marine can't lose some of his top tiers before others.