On that "swelling" of the Northern Alliance...
...I have this strange feeling that a lot of the "battles" have been Afghan Taliban soldiers dropping out of the Taliban and joining up with the Northern Alliance. No hard evidence, but from the recent reports about the last remaining city under "Taliban" control, the main sticking point seemed to be the non-Afghan Taliban members, not the Taliban itself.
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche