Here's what I know. Every unit needs to have a stand-alone program with its own leadership and its own committee, even if it is linked with another unit that feeds into it or from it, even if there are some youth and adults who double-register in order to participate. Trying to run two units from a single committee means one unit will always be shorted of resources -- or you will wind up with a single unit doing a single program (even if you count noses separately on charters).
So, trying to launch all-girl Troops come February from existing all-boy Troops (meaning, basically, a single committee with different leaders for the girl Troop and boy Troop) is very like what we've done with Venturing. And Venturing is all but dead in our Council because of it.
It's easier to do it right than to make it right. But people who haven't done the heavy lifting of starting things from scratch don't know that. They insist that you can take short cuts to developing strong new programs and strong new leaders. Alas, there are no short cuts to effective Leadership, Organization, and Program. Our new all-girl Troops are going to experience significant struggles -- OR, they will simply wind up (effectively) as part of co-ed Troops (which I wouldn't object to, but that's not what BSA said they were trying to do).
In the end, we'll muddle through and there will be girls who get to enjoy our Scouts program. But I fear that a lot of girls who join with high hopes are going to be disappointed, and a lot of adults frustrated. They deserve better. (Of course, they may just re-invent Scouting on the fly without official approval, which is kind of happening in Cub Scouts now. Separate dens for girls and boys won't last through the first year, except on paper.)
Okay, I've said my piece. Nobody wants to hear it, so I'll shut up now.