I just tried one.....APS-C wanted f/8 where FF wanted f/16 for (roughly) the same DoF and (roughly) the same AoV. Not a problem as you'll be hard pushed to find a lens that can't do f/8 or f/16.

To me selective or differential focus means carefully controlled DoF not shooting wide open...shooting wide open is usually for shallow DoF IMO. Yes there will be limits to how far you can go with differential focussing until you are shooting wide open on FF but you are likely to be shooting something very thin or something very small in the frame for me to consider it as differential focus rather than "just" shallow DoF.

Agreed about the wideangle bit...a 10-22 on APS-C isn't going to be able to match a 16-35/2.8 (unless they get the 10-22 down to f/1.7