I don't think the hashrate will explode so much. I suppose the machines which are now being sold are already mining for Bitmain ... and will be mining until October. Units will just change their location. Bitmain guys are not stupid.
Not likely - Bitmain doesn't usually mine with their units more than a few days before they ship them, when the units are selling like hotcakes (HashNest units excepted).
The current jump in total network hashrate for X11 is easily explained by A FEW of the IBeLink DM11G units being shipped and installed, plus the probable final shipments of the Baikal giant and cube models.