To say something about bounties… It would eb strange if Luffy gets a bounty now and all other SHs not... That's why I think they will join the war.
But I think Luffy will problably around 600 Mio
If Luffy gets a bounty raise it will be mostly because of ID not the war. I mean he has done a lot of stuff in the war but none of it has overshadowed his previews feats like defeating crocodile and lucci. Also what could the SH do in the war that would call for a bounty raise, if they show up(I hope they don't) it will be purly to help people escape not to fight.