Yeah, before it was the wiring pulling in a relay and could see the sparks under the playfield.

Quite common on a WMS EM and always worth checking.. can also be the source of shorts blowing a fuse as the insulation wears through.

Yep.. when it beeps the switch is closed.. I hate to add to your pain here but check the switch with it closed and a piece of paper between the leaves also.. often a switch on an EM will be in parallel with a closed switch and your DMM will read the lowest resistance and so go through the parallel switch, so youll need to disable the parallel switch.. but in all honesty, only do this if it all tests OK and you still have the fault. I think you should be OK from here and its all pretty straight forward