I think it started that summer, continued the following summer and will fingers crossed, be mostly complete after this window
Yes. I think a few will still be here next season - Dier, Winks, Doherty (though he's only been here a year), Moura, Dele, possibly Davies too
I think shipping them out along with Sissoko, Sanchez, Aurier etc is unlikely, however with those outgoings, in addition to those already shipped out, would be massive progress. The amount of new blood, along with a new manager, will bring a lot of freshness to the squad