Looks like a nice game under that filth. I also like how you parlayed a pinball pickup into a fun, family adventure!
I think you're pretty lucky. You don't have any real troubleshooting to do. Just a whole lot of cleaning, new rubbers, and some adjusting.
You're knocker coil, where you get 3 ohms - did you disconnect it before measuring? Otherwise, you would really be getting the reading of it's control circuit.