A friend pointed out that some of the older videos from what you show off are from something called a "city city asset pack" as a default map. And I believe, if I'm not mistaken, the brick textures found in the latest video are also from an asset pack. Just wanted to throw myself out there. It's taken me a long while to catch up to the high standards of current game developers, asset creation and design (probably not fully there, but always willing to learn).
I should point out if I was mistaken about your team using prebuilt assets than I apologize, I was simply implying that you probably need more volunteers on the art side of things. I should point out that the materials above the "thick bricks" are an actual purchased asset by me which I had been using to learn from, not that it's relevant but I just didn't want anyone else pointing that out.
I'm sure your team is behind and could use extra help. I don't have a current portfolio as I've fallen behind and need to make up the time to show off what I can do, but I have recently been working on a demo inside Unity for modular buildings where the player can walk inside and out without loading times. This picture is an example of the texture work done for the building and how it eventually came out in engine:
May not look like much, but it was a ton of work and was done from scratch and it is 100% tileable. I'm proficient in Unity but am willing to learn for Unreal 4, of course.
On another note, I'm also a proficient writer, amateur programmer and have worked on a few VR demos. They usually say not to show off too many skill sets on a portfolio for fear of trying to show off, or someone not believing them maybe. But I just wanted to throw that out there. Let me know if you need another volunteer and good luck on your project.