The main character/s of the last Yas Forums related media you watched/read is now a part of the One Piece world...

My theory is that Oda wanted to kill off Ace but realize after doing so that ace was one of his favorite characters.

Let's be honest manhunter would probably be part of the Revolutionary army with the rest of the league if they were in once piece

>Ducktales

Pretty well, consider they also love adventure. Although I can see Sanji trying to make duck soup out of all of them

would he have a martian fruit as a mythical zoan?

Holy shit Scrooge would shit his pants if he heard about the One Piece. He would be a yonko with all his territory and money, he'd probably have conquerors, and would be a too 3 contender for pirate king

chopper wouldnt let him them eat another talknig animal

...

They would be Fishmen so that's highly doubtful.

Ducks arent fish

Scrooge would just by Duck Wapol but less combat potential. Getting by via money and connections that he build via his money. Would not risk his life for One Piece that might or might not be treasure. Would face discrimination because he is a Fishman. Dunno if he would do business with the Celestial Dragons. Tons of potential there but the moment he steps foot on their island or appear in their presence, they will attempt to enslave him.