I agree with everything you said here, but why the fuck is your conclusion that Pedro will join?
Many many reasons. This will be a summary. Expansion and explaination on request.
Unique traits: Spots, Prehensile Tail, Electro, Missing piece of left ear, Left eye scar over missing eye, Quirk of standing on top of objects
Ship role: Ship Guard; Pedro is the Captain of the Guardians. Meowban Brothers, the only Ship Guards to be introduced as such that happen to be cat-themed.
Already has a bounty of 382M. Only other Mink with a known bounty is Pekoms at 330M. Already on the WG's radar.
Flashbacks
Lost someone important in WCI. Pedro used that traumatic experience to help the Strawhats get a copy of a Lode Poneglyph which directly correlates to Luffy becoming the Pirate King.
Pedro met Gol D Roger the Pirate King. Similar to some other crewmates relating to Roger's crew.
- Luffy with Shanks
- Franky with Tom and Oden
- Brook with Crocus
Kuma seems like a character that will die. He is not himself anymore. He has no role now. The Devil Fruit power he has is powerful and would be useful for the Strawhats as a "end of game aircraft" or to speed the narrative when necessary. Kuma protected the Sunny essentially being a Ship Guard at Sabaody during part of the timeskip. That Will may be past to someone and I'm thinking/hoping Pedro. The Paw Fruit on a Cat Mink makes too much sense.
Bonding with Strawhats
- Told the crew about his past failure on WCI.
- With Brook during their mission to copy the Lode Ponegliff.
- With Jinbe during Wedding Cake surprise and escape.
- Saw Chopper save the poisoned Minks. Both were hot because of fur during ride to Tottoland.
- Thinks Nami as a demon when escaping on King Baum. Argued with Nami about Pudding.
Eyepatch. Oda is saving it. Pedro's big return is my guess.
Ninjaguardian (portmanteau)
Ninja Jaguar Guardian
Luffy wanted a ninja but yet didn't get one. And it's not like Luffy didn't have some choices. But clearly they were not Strawhats as Oda kept them in Wano. So why hype them in the first place for Luffy not to get one? My guess is those aren't be the ninjas Oda wants in Luffy's crew. If this puzzle I've put together has credence then Pedro may become a Copycat Ninja similar to Kakashi from Naruto.