After about 6 hours on Saturday... methodically removing/ resetting/shimming/bracing each riser and tread... then spackling, priming and painting the risers... the stairs are now SAFE and SOUND!!!
My husband rated this project a 5 out of 10 on "our" Home Improvement scale (I think it was more like a 3... but I was mostly supervising... LOL)... I think too he was mad that he dropped his drill and torpedo level under the steps (so whoever fixes the steps next will find a couple of tools)
Anyway... this project is done... and I feel better about the steps!