Problem with Complete Project

I have a product that is actually an asset pack, but Unreal support changed distribution method to Complete Project, because there is Epic character for testing there.

In fact, this did not make sense, it would be easier for me to remove this character and sell the product as Asset Pack. But I am a beginner and I did not know about the dangers awaiting me around that turn.
Several people bought my product and there were no problems.
However, today one buyer left a comment that he could not add these models to his project.

I wrote in Support can I change distribution method to Asset Pack without changes in the project. But they say that under the new rules, this should be Complete Project.
I will have to remove the Epic dude and blueprint, but I will have to wait until the new version is approved. I would like to help my client as quickly as possible.

Can I add Complete Project product to my project? And How?
As I understand it, it is impossible to manually transfer assets to another project, otherwise all textures and materials will be absent. But As I said above, several people bought this product more than a month ago. No one declared themselves, from which I concluded that they were able to cope with this.

It is possible to transfer assets and their dependencies using Migrate.

Did they point out under which rule it has to be a Complete Project. I don’t see any such change in Marketplace Guidelines 1.4.4. Hopefully this is just a misunderstanding and we are not about to get some new weird rule :confused:.