wall mounted faucet

Hi there. My girlfriend has found a tub filler she likes that is wall mounted. An issue we’ve run into is that she also would like a hand faucet for the tub, and the valve that comes with the tub faucet she picked out is supposedly adjoined to the faucet, not allowing for a diverter to be used...

im installing a bunch of wall mounted lav faucets which I have never done before. Just wondering where and how the shut offs are usually plumbed. My thinking is that you just come out of wall, have an in-line ball valve, then go back into wall and tie into the rough in. Is this how it’s done...