Hello!
I did some research on this topic and found something that kind of answers this question but not entirely.
“Each such product built using content purchased on the Marketplace must be a standalone creative work (such a game, simulation, or video) in which content is merely a component and not the primary focus.”
(Source)
So the answer is probably yes, but the extent is undefined. When does something become primary focus? If i use my custom drawn characters but use backgrounds from marketplace content (which define their location/environment), would that be considered as a primary focus or not? Since the main story is about characters, then hopefully it is allowed to do so?