For #1, take a look at what causes the lock relay coil itself to energize (at E12). When any relay coil energizes, all of the switches at that relay change state (closed>>>opened and opened>>>closed). In the case of your lock relay, the (normally open) switch depicted as connecting to that branch of the general illumination circuit (in the backbox) will close when the lock relay coil energizes. The other lock relay switch shown to the left in blue likewise closes, and heads off to illuminate the GI circuit on the playfield. (Note that the schematic does not show the associated jones plugs that connect the cabinet, backbox and playfield wiring).

At E12 you can see that the closure of EITHER of: a) the left flipper button OR b) the depicted switch on the coin relay will energize the lock relay. The moment the lock relay energizes, the N.O. "LOCK RE" switch also depicted will close, which provides a 3rd (permanent) path to energize the lock relay. In this case, the lock relay "locks on" to provide permanent general illumination until the game is powered off. If this lock-in switch were not there, the lock relay would de-energize as soon as the left flipper button were released.

What causes the coil on the coin relay to energize? Go find that coil elsewhere on the schematic and take a look. It is really just a cascade of smaller puzzles.
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