Disney Rips-Off Splatoon and Arrowana Mall and Puts it into Disney Infinity 3.0

They'll either just scrap it or they're going to try some bullshittery in court.

I'm not sure they can get sued for this... unless there's some other form of blatant rip off (such as a direct copy of maps/weapons or coding) that I'm not aware of. I don't play Splatoon so I dunno. But Splatoon isn't the one who came up with the concept of colouring the map so you get the most area covered with your colour. It's even in older Mario Party games albeit at a much simpler level. If they could get sued for using a game concept then wouldn't the first military FPS be entitled to sue all following military FPSes? Or all those minecraft rip offs.
(edit: I know you didn't say they'd be sued but that's what I assumed you meant by the legal department stopping them. Why else would they?)

Gameplay and game modes can't be legally registered in any way - not by author rights, intellectual properties or patents.

If that were the case, Mario and Doom would have been the final games in the platformer and FPS genre, because everything that came after them uses fundamental mechanics that were "ripped off" from those.

They'll probably say it's a Disney-created squid-inspired paint battles. Not a rip-off at all, just an inspiration.

Disney created the level. Their official trailers for the game mode show them playing in it.

That it is

I see. Also I saved the link to read later.

It's for rich white people /o/