As it turns out (see my post just above), adding the M.2 SATA drive in the WWAN slot was fairly easy, although I did have to learn how to initialize the new SSD for File Explorer to recognize it (something I’ve not run in to as such when cloning drives in the past - maybe the cloning software just took care of it.) The initialization is easy once you know how to get to it via device Manager.
“Device Manager”. Sheesh.
Good news.