I agree with MegMeg on this - your first loyalty should be to your girls; the politics of other people can be dealt with creatively somehow.
I do a similar thing to aeh - my three boys are at home from me, but I work from home. They do their own thing for the most part and I do stuff as and when I can with them - my on paper saying is that I am trying to help create independent learners. They do attend classes for music, sports, science and a few other things as base for their "learning" but our hands on time is in evenings and weekends.
My kids are almost 8, 6 years and 3 (almost 4) years old. it works for now. we are about to have our semi annual sit down chat about learning goals for the next 6months... I think that what you describe would work very well - I'd consider starting now and for both of them though. The desire to NOT get out of bed to go to school is a big deal to kids - and it has a knock on effect very quickly.
