success!

Guess who just played her first game of Royal Flush in a month?  THIS GAL!
I am still unsure at how the playfield stuff is turned on/off in the schematics, as it doesn't really get to ground, but I did see the Q and AX relay were involved, so I searched for the wire colours and concentrated on those switches.  Turns out it was the secondary make/break on the AX that was wayyyy too open.  5 minutes of adjusting, and CLACK, the flippers now worked, the playfield was now live!

I played, and it was good.

A problem still persists:  The lights for ball # and player # aren't lit, but checking the schematics the AX is involved in both of those as well, so probably just a straightforward adjustment there.

After I get in some good games I will address that lighting issue.  Before I get back to my original list of issues with the game, I learned something from the Gottlieb Parts Manual.  The playfield has a number of difficulty settings, and the Joker standups can be adjusted to be easier.  Right now they are in the conservative position, meaning nothing less than a dead-on hit will be able to trigger it.  The surrounding rubbers will catch any ball that is slightly askew, and send it away.
But more about this change in another poster.  Right now, off to play Royal Flush!

EDIT:
Getting the ball # and player # lights back on was easy.  There had been issues with the bonuses being added, but after fixing that light issue, that problem has disappeared.  Let's see if it comes back later.
What was less easy was the make/break switch that kept the playfield active.  It was quite difficult to bend it to a reliable spot.  The center of the 3 switches had a mild bend in it, and I think that, plus contact corrosion, played a role in its fickleness.
 One new problem discovered:  the game is not advancing past player 3.  No worries, I'll stick to 2 player games for the time being.  after all I've been through, tracing the player advance circuitry seems like a novel thing to do for pleasure, but I'll save my confident attempts at it for tomorrow.