First of all, they're all delusional.
However, Zoro defeating Kizaru is the least delusional because the only reason Zoro can't defeat Kizaru is because he's too weak to defeat a mid top-tier 1v1.
Kid defeating Shanks is 2nd most delusional because of the same reason as above, however, Shanks has his entire crew plus Elbaf allies meanwhile Kid has Killer and his merry band of fodder. At least Kizaru doesn't have any strong allies apart from Saturn. Kid is too weak to defeat a mid top-tier 1v1, let alone a mid/high top-tier surrounded by a superior crew.
Law defeating Blackbeard is the most delusional because of the reasons stated above and because Blackbeard is the main antagonist. For him to lose here would be utterly retarded from a narrative perspective.