I picture this fight being super ugly and not enjoyable. The height differences would be too insane I actually think Castano would tear Fundora up to the body. Castano is too short, and fights too low for Fundoras money punch the uppercut to land. Whereas Fundora has too much body for Castano not to beat up on. Interesting most of my fav fighters have great uppercuts haha, I like the toe to toe style tbh. I actually feel like Harrison would box Castano's nut off and Castano doesnt hit hard enough to get him out of there which he would need to. Castano short arms and legs won't be able to bridge the gap long enough to wear him down. Harrisons losses have all been to tall, long guys who he couldn't keep at range long enough. Fundora would walk Harrison down, Harrison just can't get enough space. Fundora covers the whole ring and forces you in to a gruelling match up.
Fundora's pressure definitely wears Harrison down. The other two matchups are more interesting to consider.
Big fan of Castaño, but how the hell would he even reach his face at 5' 7"? Fundora is almost an entire foot taller than Castaño.