With a bit of work that could be done, I suppose. Actually, I was just about to look into that as well for a similar case, but have not come around to it yet.
The idea is to create a custom Text field for Creator, that is hidden from the post edit screen by contradictory logic, such as: “Show only if another random field contains any value and contains no value at the same time.” Then we would hook into the post edit screen whenever a post is saved, check if it is a Project, iterate the Repeater, fetch each Creator mentioned, and save the data in the hidden field as JSON, so on the Creator template it suffices to get_field( 'hidden_text' ) and unpack the JSON without querying the Project post type.
It would cause a bunch of additional database queries every time a post is saved, but that is trivial, especially if the alternatives are to either cause a bunch of additional database queries every time the front-end is called, or do it all manually and go insane.
