On your 3rd pic the ball count unit horizontal switch stack, the lower normally closed switch looks bent and not closed correctly. On the 1st pic shouldn’t the red spring connect to the post just left of where it is now?

http://www.pinrepair.com/em/index1.htm

Probably a good idea to go through all the stepper units I would imagine some are gummed-up

Yeah that 1 switch blade looks pretty bent-up a good switch adjuster tool is good to have https://www.pinballlife.com/ultimate-leaf-adjuster-tool.html along with a dental mirror in some cases

score motor switch loose stack (resized).jpg
looks like a loose switch stack on the score motor , first straighten and tighten things up before adjusting the blades ( if needed )

fan-tas-tic stepper out of square (resized).jpg
I also noticed on whatever stepper unit this is it appears the Bakelite plate is "out of square" causing to fingers to be misaligned.

Welcome to Pinside and keep us posted

https://online.fliphtml5.com/vrtyz/porq/#p=11

The lower switch blade here is what member pinballdaveh was talking about
fan-tas-tic Lower blade (resized).jpg

Does this reset pawl move freely ? the spring should probably be on the other side of the frame but may be ok where it is.
fan-tas-tic reset pawl (resized).jpg

I have a United puck bowler with a similar stepper unit.
IMG_2447 (resized).JPGIMG_2448 (resized).JPGIMG_2449 (resized).JPGIMG_2450 (resized).JPG

The playback on the video you posted I had troubles with ( perhaps someone with a better computer will have better luck )

The fact that the machine changes player indicates that the player up unit are at least partially working. Are the player reset relay and player unit reset working properly? If the player reset relay isn't working it may cause the player up unit to change to next player when it shouldn't. Also check the reset relay, as that one also controls the player unit reset. (I have a similar problem on a Segasa Casino Royale, which is based on Williams parts)
Player_up_unit (resized).png