Update... last night I installed a jumper wire to replace the burned out trace connecting J902-1 and the center leg of Q5. I booted the game with the drop target in the up position... and it dropped-- but then it continued to "machine gun" trying to pull the target down (when it was already down). So obviously I turned it off. I removed the jumper so my kids can play in the meantime.

Does that mean my next step is replacing Q5?

The switch is fine. I don't quite know how to describe what was happening-- and I didn't want to do it again with the playfield up and cook the coil-- it got quite hot quite quickly. The coil pulled in and dropped the target, and then kind of chattered with the target in the down position-- it wasn't like it was releasing the coil and pulling in again. But there's was just a tiny bit of visual up and down as it was chattering-- I suspect the other coil was trying to simultaneously raise the target.

Pleased to report that I can "close the ticket" on this one.

A buddy who fixes (non pinball) electronics for a living came over last night, and helped me change out Q5, and we added a jumper to replace the blown trace.

It fired right up and worked flawlessly. Hopefully it will not be a recurring problem, but I think we can consider this one resolved.

Thanks to all who helped me troubleshot this, and an extra heap of thanks for Zaza-- for the patience, expertise, and supplying the images that ultimately helped me to resolve this one.