Hmm, well it seems like we have three options then. We can continue, and hope that the other two people actual do join. Or we could kill the roleplay, which would be a shame, and not something I would support.
Or we could try to redo it. Take a break and rework some things with the story, polish things up, then start over again and see if that works.
Whatever you choose, I would hate to see the roleplay get shut down, its a fun concept and world that you have created.