A 1v1 duel between Kin'emon and Kanjuro would be pretty intense. They're the two Scabbards we've known by far the longest, both of them jumped through time, they're the only two that use DFs (unless Shinobu is a Scabbard now), and it's a battle over Momo with Kin essentially acting as his fake father. Kin'emon might feel as the "leader" of the Scabbards it's his duty to take out the traitor.
They should be even in terms of abilities. Kanjuro posses hardening haki, they're around the same age, most likely share a similar amount of battle experience becoming Samurai under Oden, Kinemon can cut flames but Kanjuro and the full potential of his DF should add another level to his capabilities.
Though who is supposed to take on Orochi with this stuff playing out? Zoro gets stalled for more than a few pages? I guess Orochi manages to slither away until the end.