Look, I'm not trying to dissuade anyone from anything. It's just that this community has seen this type of post dozens of times before, and as far as I can remember none of the mods that have started out with posts like this ever go anywhere, for one simple reason: Coders are extremely jaded people. You'll be able to get mappers easily, but for coders, you're going to have to bring a little more to the table than just being an idea man.
Coming from personal experience with failed mods, and experience watching other mods in the community die before they've started, I've learned that the best advice I can give to someone starting a mod is:
1) Go into excruciating detail about your mod in your post. We may have the rare map thief in the community, but nobody is motivated enough to steal an entire mod, and nobody will be interested in joining without more information, which most people will be too lazy to request through email. You have to trust that nobody is going to steal your ideas, in this community the odds of that happening are very, very remote. Everyone else is too busy dealing with their own supar-sekrit uber ideas.
2) The project leader ABSOLUTELY HAS to have programming skills, plus a little bit of mapping knowledge but that's not as much of a requirement. Just knowing your way around the editor and being able to do basic stuff, enough to build test levels, will suffice. Your role as leader will be to get the project off of the ground by coding the basics, making test levels, and organizing testing and feedback. Once a basic game has been made, release it to the community while asking for help. Having something tangible to mess around with will go a long way in finding talent, ESPECIALLY with programmers. They don't seem to like being bossed around by an idea man who isn't contributing anything to the mod.
3) Don't use someone else's IP (I know this doesn't apply to you, but it's still a major point on my list to new mod makers). It should go without saying, but it's amazing how many mods have started out like that and have quickly been squashed by cease and desists.
I'm honestly trying to help, I'm sorry if you took it the wrong way. It's just frustrating to see so many mods die before they've even started, and watch the team lose interest in the community and the engine.
If this is your first foray into the Unreal engine, in your spare time I would immediately start getting into coding, starting with small weapon and mutator scripts, then working your way into different areas until you have a solid grasp of the inner workings of the game and how everything connects. I'm not saying to completely abandon your mod idea, but when it comes time to make it, you should be leading the charge.
Good luck, and welcome to BeyondUnreal and the community!