There's another Ghost Master 2 project using Unreal that may or may not be going on right now. I emailed them a few days ago to see what was happening with it, but no response yet. Maybe they could help you and your friend, if you're willing. It looks like you have done more so far.
Nisk, it will be good if we'll have support. I can't explain now more, now we creating a base of engine. But I want ask users, prepare some ideas for levels, ghosts, and story in this thread. But please do it centrally.