Infinity's Toy Box is like the only place where they even go that far with mashups. I mean look at the strict rules they put Kingdom Hearts under, only the Mickeyverse characters and Maleficent are allowed to visit other Disney settings. The convoluted plot focusing on all the anime rejects in the sequels exists entirely to compensate for that lack of freedom with Disney stuff.
Also, if Thor can exist in a universe with Howard the Duck or his own talking frog counterpart (
No I'm not kidding), not to mention all the dimension hopping stuff you find in pretty much every cape comic, I don't see why interacting with Disney characters in some non-canon Super Smash Bros-esque "living toys" setting should be a big deal.