I think Brook Feeding his Guitar Big Moms Soul Soul Fruit would be Awesome, the possibility of this happening is Zero i know, but imagine the Soul King playing his Guitar like SpongeBob Purple Hell fire on his strings as he plays bringing to life the Emotions from all those listening to his music ready to fight for him .
As for Kaidou i think the dragon Motif would fit somebody like St. Charlos as he would Represent the foul aspect of what it means to be a Celestial Dragon by LITERLITY being a dragon and a Celestial.
Charlos severe lack of strength would be overcome by the Fruits innate ability to be the "Strongest" an otherwise harmless opponet is now a somewhat reasonable threat. while not having Kaidou's combat ability or Conquerors haki he would still be a formidable threat especially for the inexperienced which is why i think a matchup between Momonouke vs Charlos would be pretty cool is as it would Mirror Ryuma Slaying a Dragon to Protect the Land of Wano Charlos becoming drunk with power losing his mind and becoming a wild beast Using his Fruits abilities in more Vicious and destructive Ways Charlos reckless nature overwhelming Momonosuke Swordsmanship.
Charlos now having the necessary Strength "to be Fee/ Do what even i want" Could even be seen as a Luffy Parallel
Charlos being seen as a capable fighter just too weak mentally to be strong taking shortcuts similar to Blackbeard
the Gap in strength between the two could be Highlighted by the Fact that Momonosuke is a replica. Natrual vs Artificial

As for Kaidou i think the dragon Motif would fit somebody like St. Charlos as he would Represent the foul aspect of what it means to be a Celestial Dragon by LITERLITY being a dragon and a Celestial.
Charlos severe lack of strength would be overcome by the Fruits innate ability to be the "Strongest" an otherwise harmless opponet is now a somewhat reasonable threat. while not having Kaidou's combat ability or Conquerors haki he would still be a formidable threat especially for the inexperienced which is why i think a matchup between Momonouke vs Charlos would be pretty cool is as it would Mirror Ryuma Slaying a Dragon to Protect the Land of Wano Charlos becoming drunk with power losing his mind and becoming a wild beast Using his Fruits abilities in more Vicious and destructive Ways Charlos reckless nature overwhelming Momonosuke Swordsmanship.
Charlos now having the necessary Strength "to be Fee/ Do what even i want" Could even be seen as a Luffy Parallel
Charlos being seen as a capable fighter just too weak mentally to be strong taking shortcuts similar to Blackbeard
the Gap in strength between the two could be Highlighted by the Fact that Momonosuke is a replica. Natrual vs Artificial

