Maybe, since they can control two-thirds of the needed phenomena, being energy and momentum, IDK if they could control, increase, and decrease mass tho.

Given how any measurement is, for some reason unknown to me, a vector, you could control anything you want

Also mass is the same as energy, literally, so it really isn't a problem to control it (most of the mass of atoms comes from the gluons holding the particles together, which have got a mass which is simply energy in the Higg's field. I've extremely oversimplified it but that's the idea)