The question would be, do you want to fight Disney lawyers to make the argument that your use was not as a trademark, represented as Disney, or that it might cause confusion? With or without a disclaimer.
For trademarks, there simply is no safe harbor, and thus no conditions under which it can be removed. That means there isn't a codified process for YouTube to follow; but the stick they can be beaten with at the end of the day -- infringement litigation -- is the same in either case. You can bet they'll do what they can do avoid it.
If you're making a work derivative of Steamboat Willy then Disney has no basis to sue you, regardless of what trademarks they claim.