Wow. You are considering a 'suicide mission' of sorts. I don't know anyone who has done this, but that doesen't maen it hasn't happened.
Just remember, you would have to maintain the facade of all facades. I don't see how anyone could keep that up year after year. And when you get to the point where you can't keep going, it will be tougher on you & your family then if you hadn't started at all.
I can understand what you want to do, but I don't understand what advantage you would gain by joining. If you or anyone else can think of one, please explain. I think that it would be a tremendous DISadvantage. You are where you want to be (and where you want the family to be)...on the outside. My advice is : don't make things harder than they are already. Do your research, ask the right questions at the right times, but keep your distance from the cult.