G Rank Zinogre
Smash Apprentice
I'm going to make a somewhat bold claim and say that I don't think Incineroar was in the roster at any point. Absolutely nothing suggests this besides word of mouth with shaky sources. We've no visual evidence of him being there. If the Grinch leak, and thus, the 4chan leak from September 28th are to be believed, he was not there at any point. Finally, and this is merely my gut feeling, but I don't think Sakurai had him or any other new Pokémon on the mind seeing as he was tasked with also fully recreating three Pokémon. And, as Pokémon has the largest amount of unique fighters in the series (Eight unique, one clone/semi-clone), I think it stands to reason that he might not be interested in adding another.