Luffy could get 4b if BB is credited for Garp/Law and gets a bounty boost, that also means Shanks getting credited for Kid and Bart. which is most likely now.
Luffy=Killing VP/Buster call/Kizaru?
Blackbeard= Garp/Law
Shanks=Kid/Barto/GB? (can't remember if GB presence was known)
But I could also see the Garp credit going to Kuzan first pirate bounty and his other crew mates and that 1 guy that was complaining about BB getting all the fame.