I created an entire system and used assets just to represent items, however, I came across a review stop that presents the following question:
Should I change it or explain that it is from their free pack? I totally understand if i have to change it because whether i like it or not, this pack was from a producer that probably paid for the rights to the brand of the rifle.
How to proceed?
The model is from here: Edith Finch: Sam Room in Environments - UE Marketplace
I’d push back, but asking for an explanation.
Point out specifically what asset pack the item came from and that the asset pack notes " UE-Only Content - Licensed for Use Only with Unreal Engine-based Products".
If there is ANOTHER licensor that you might be infringing on, I would hope Epic could at least articulate it.
Right? But where could I point out these issues? By email? Through my product page?
I’d likely do both. My point being you’re visible in responding to this.
I’ve not submitted a product yet so I cannot say from experience, but I think I would do both. At least point out to the reviewer that the asset is in-line with UE marketplace assets and their license but that you are checking as well. Additionally, it’s my understanding that (essentially) any marketplace assets are open to use in your own products so long as you use them inside the Unreal engine.
For Epic, I guess email, yes. 
When you registered the product, did you get anything therein that tells you where to follow up w/concerns?
Sorry for the delay, I’ve been busy. Yes, I think I will explicitly state on my product’s showcase map that the assets are allowed and free to use. And also yes! I received an email to ask any questions, doubts, etc. However, honestly? They are taking a long time to respond. 
But, let’s see what happens. I put in the documentation that the products are free and “all of these assets may be used under the following conditions from Epic Games itself: UE-only content - Licensed for use only with Unreal Engine-based products”