the hold relay does not power until the player up unit steps, then it stays powered forever unless the game is tilted or the start relay powers.

your results in post 1 and 3 conflict and don't really make sense ... either your jumper wasn't making great contact or you've got flaky connections and stuck closed switches.

a simple test is turn the game on and manually close the player up unit EOS switch. Usually it's activated by the step-up coil plunger arm. The hold relay should power and stay powered.

if you're testing the game with the playfield tipped up, the reset sequence may not complete until ball trough switch #1 closes.

assuming 1. on the meter is the same as when nothing is connected to the meter (i.e. infinite resistance), then yup, get another resistor and go from there.