About Yamato waiting for Luffy would be a complete bullshit for plot comvenience, Luffy has been already Ko two times, he shouldn't be able to fight again for at least a fucking day, but something like i have the bad feeling that he will wake up in 15 or 20 minutes and be 100 times stronger.
Oda and his shitty writting is really insane, Page one was easily ko by Big Mon single punch, but a fucking bloodludter Kaido can not ko Kinemon, this Onigashima war arc is a complete joke with pure 0 tension.
KAIDO downplayer head canon so far:
Kaido 20 years younger who was slashed by Oden = current prime Kaido.
Kaido 30 years younger who was captured by the navy and experimented by vegaponk = current prime Kaido.