Realistically, there's no way it'd have a separate hitbox. That's an actual gameplay difference. They don't do that for costumes. Because any gameplay differences require another slot, which in this case, isn't worth doing. It'll most likely be a phantom hitbox.
Also, that's a fun leak. Leaker did a pretty decent job at it. Reasonable photoshop.
It was Microsoft Paint actually, i dont know how to use anything else, a friend linked me here.....i made that image to promote and campaign k rool and dixie and how they might look ingame, someone stole the image, made it blurry and spread lies around even though i specifically asked for this image to not be a leaked image.
im sorry all for that.....the k rool model has been linked above, its not the sjwcyberwolf one but its similiar k rools portrait is custom made, dixie kongs portrait and model were ripped straight from tropical freeze on switch, the image of kongo jungle i took from the smash ultimate e3 direct, ridley is also ripped from ultimate, the barrel item was also taken from e3 gameplay, sorry for the leakers spreading this image around.
here is og image