Good news! My other Lisa shipped today, and with a bit of cleaning and swapping of cards, it works! It boots fine from a ProFile drive that (surprisingly) still works, and contains all of the old owner's accounting files...
Anywho, my next task is getting the Widget drive to work in this machine. However, when I connect the drive and try to start the machine, my power supply clicks repeatedly as long as I hold down the button. Is this a voltage adjustment issue?