Hey I just finished watching the 3rd and 4th marathon length videos and I’m really enjoying following along. I have quite a bit of programming experience so some of it is basic for me and sometimes I’m a couple of steps ahead of you, pre-empting where your headed. 
Occasionally I pick up on a problem and I find myself talking at the screen, saying “look over there, that’s the problem!” Hehehe 
However I’m also learning a lot of stuff so it is really good. Not really possible, but wouldn’t it be fun to actually do this sort of thing over like a live twitch or something so we can actually chat in real-time as we go.
One point (not sure if this matters anymore as there are many videos for me yet to watch), but in video 4 you are redundantly setting your Temporary Int variable to the index of “self” only to then overwrite that value with a random Int in Range before Temporary Int gets used for the first time. So you can actually remove that first set on Temporary Int.
Oh and in response to your question at the end of video 4, this might be too late but… how about UE marketplace content… hehehe!