I understand the reasons for thinking about maintaining two households...but my initial reaction is that family is everything--is it really a good idea to have everyone living separately? Isn't true stability a together family? Regarding part time residence w/H and S & D...teens need full time parents. Even good ones.
In my experience, GAL is 20% physical, 80% mental. But that's just me. I can't see that a tour of duty in Afghanistan is preferable to joining a club or taking a class for yourself. Back to D14--she needs her mother present in her life. Especially if things are rocky in the M. If she were 18 and on her own--entirely different scenario.
You know your sitch much better than I. It all just seems like a perfect opportunity for you-know-who to creep the door open a few notches and split y'all up.
(I'm really not trying to beat up on your brainstorm--just sharing first impressions--say the word and I'll take it easier on you next time. )