Seems extremely interesting...
I have a character idea in mind that I've been meaning to use for a while, and I think it would fit perfectly in here. Would you be open to someone playing a sort of temporary antagonist character for a single mission? It would have bit of a "monster of the week" flavor to it, so to speak. It might also provide people with a convenient way to introduce their characters. If you are interested, I could send you the details via private messaging. If you aren't, it is perfectly alright as well, I just figured it wouldn't hurt to take a chance and check.