Now that you've confirmed the switches are ok, your solenoid tests indicate a communication issue from the MPU board to the Solenoid Driver Board (SDB).

You've got an open circuit on the signal known as "PB2" between the MPU board connector J4 Pin 2 and the Solenoid Driver Board connector J4 Pin 4
Wiggle each of these connectors one at a time to see if either "fixes" the problem. Which ever connector fixes it needs to be repinned. If it's the SDB connector, first check the back of the SDB where the connector pins are in case the soldered joint is cracked/fractured and resolder it if needed.

Technically speaking, below is a binary list of the four "PB" signal states between the MPU board and the Solenoid driver board that are used to select a momentary solenoid to activate. You may notice with the condition of your fault, signal PB2 is always stuck on logic high (1) 5volt level.
When the Left Pop Bumper is selected, PB2 should change to a logic low (0) which is zero volts. However when this signal is high (1) the Drop Target Reset is selected which is what's happening in your scenario. Ditto regarding PB2 for your other incorrectly activated solenoids.

PPPP
BBBB
3210
====
0000 - N/A
0001 - N/A
0010 - N/A
0011 - N/A
0100 - N/A
0101 - Knocker
0110 - Outhole
0111 - Grotto Kickback
1000 - Left Pop Bumper
1001 - Right Pop Bumper
1010 - Bottom Pop Bumper
1011 - Left Slingshot
1100 - Drop Target Reset
1101 - Right Slingshot
1110 - N/A
1111 - None

No worries, I often advise people in these tech threads without explaining how or why which doesn't help people learn. So hopefully me going into detail will help someone along the way. Good luck diagnosing your Centaur!