Was wondering what happens if you use Saruman’s staff to lower the doomed value to 0? Does it still count as having played a doomed card for the purposes of readying Saruman, etc? Seems like it would to have synergy but I’m unsure. Anyone know or have thoughts?

For me yes, it's a doomed card which make you raise your threat by 0

Agreed. I think that's the point of the synergy between saruman, the staff, and the doomed events