Two handle tub and shower to one handle?

Totally gutting and re-doing bathroom. Currently have 2 handles, tub spout and shower head. Doing most of the work ourselves. Plumber will be coming to install shut off valve for bath. Does not have one now. Fixtures will be in brushed nickel. I have only been able to find one brand of tub and shower 2 handles in this finish, American Standard, special order. They call it satin finish, which would probably be close to brushed nickel. Much more options in one handle. Is it a big job for the plumber to change this? House is on slab. Water lines are copper. They are easily accessible in a closet.

While the walls are open it is a piece of cake to change the plumbing. Any competent plumber can do it.