The point is that WB was already a special case. Buggy first stated to mever touch one of WB crewmates or you will anger him and make him come after your ass, whoever you are, the wealest pirate or the navy itself.
So I can very well see Shanks challenge the WG to save one of his crewmates with all his might (even because is crew is small and strong so every crewmate is like a family member, same as SH.. And WB pirates and Riger most likely), then first of all try to resce him in the weakest spot,like Luffy trying to save Ace when he was in Impel down then I suppose coc slash to defeat fodder, his mates vs vice admirals and admirals, gather all his allies, something like WB did pretty much. Maybe since it is Shanks we are talking about even try to deal with the Gorosei directly lol
Kaido and BM on the other hand wouldn't care about it so much if it isn't something as a big asset (like Pudding for BM) and or very close to him / her (ycs).
Anyway Kaido maybe try to open things up with the numbers (same as Oars jr for WB) and then have his men try to enter, King try to reach the prisoner flying (this would be almost exactly like Marco), try to gather everything he can as well.
BM use Zeus and Prometeus, her ycs, Streusen and his powers to destroy defences.
The problem is that BM and Kaido's crew are overall weaker than WB. Weaker yonkos, weaker yc and probably weaker crews as well. The marines would have to think something to bypass Kaido and BM hard skin but beside that it would be easier than Marineford for them.
(ok he'll lift 1, but not 2)
