Seriously, my friend, let me take a look. I tested it in Unity and it works, but let me fix it or maybe separate the animations, because I think that’s what’s missing in this package. Which engine are you using exactly so I can look at the problem from there?
5 days ago (+1)
For now, I'll leave the characters without animations so you can create the skeleton or add your own in Blender. The weapons will remain separate for the time being so you can play around with the models until I resolve this issue and they work in your game engine, as they do in Unreal and Unity. I think I know what the problem is with the horse, and I apologize.
5 days ago (+1)
I know exactly what the problem is. I made the weapons look right in Unity, and from there I extracted the FBX file, and maybe that's what's causing it to break in Blender, And that's why it doesn't work in your game engine, I think.
4 days ago(+1)
Hi, I'm still working on fixing the problem because maybe I don't know how the engine works. But I left you a folder with all the characters and objects without animation so you can animate them yourself. I don't know why it's not accepting animations from this engine yet, and I don't want to delay you, so I'm leaving it like this for you to add the animations you want. Sorry I don't know how to fix it right now.
Massive thanks for working overtime.
I think there might be some issue with Blender import? Idk, I tried your newly uploaded mesh - all I did is import it to Mixamo, apply - Idle animation and when I import it back to my game engine, this happens - 
I hope there is a fix to this.
I've worked on many horror games and used many animated models, but this is the first time I'm having the issue, ever. Just odd.
2 days ago (+1)
I found the solution. It took me a while to find it, but I managed it, so I'm going to fix each one so that it now works correctly in your engine and you can add animation without problems. Let me know if anything seems off.
2 days ago(+1)
Okay, I changed the FBX files. They're in the same folder without animations, and I tested each one in the engine and it works fine.
Well, my dear friend, sadly, it didn't work. But, I found the solution - I baked all the textures into one and it is working perfectly.
I apologize for wasting your time, because it was clearly my game engine's fault and not you at all. Although, I sent you some donation as a token of gratitude. I'll be using this pack in my upcoming game and if it does well, I promise to donate more in the future.
Best to you and thanks for the help!