Before attempting to create a fake world, it would be prudent to actually speak with those you intend to involve. At the very least to determine if they're even interested in participating in your larp.

I don't know who needs to hear this, but you can't forcefully destroy people's lives and just expect they'll go along with your plans for what you want to replace them with.

If you try to do that with the entire world, you're going to end up screwing with things you don't understand.