Luffy did say during WCI that he wanted to defeat "the one billion berries man" then he himself surpassed the billion mark. It could imply he will every time surpass the bounties of all his opponents, but the idea of him jumping from 1.5 B to 4.6+ is insane. I just can't see it happen and maybe I'm wrong.
Same for Zoro and Sanji, I believe they're supposed to beat King and Queen but it's hard for me to believe they will surpass their bounties because it would be a hell of an increase. I'm more open minded in their case though, as it's far more believable because the jump wouldn't be nearly as huge. Zoro getting to 1.52 B and Sanji getting to 1.33 or 1.377 B wouldn't shock me but that would be way above my expectations.