First thing you need to do is get the game straight into switch test mode when cold and watch what switch numbers the MPU board *thinks* are closed until it reports "0". These switch numbers will help pinpoint which switch strobe/return lines on the MPU board you need to concentrate diagnosis on.
Just make sure J2 is disconnected from the MPU board before you power on so no actual closed playfield switches invalidate this cold test.

BTW, is this a battery corroded MPU board? Can you post a picture of it?

Thanks. Some corrosion around the edge but otherwise clean.
The important part of the equation is the switch mode test result. What did you get?

If you put your multimeter on high resistance measuring scale, do you measure anything across that suspect Miss January switch capacitor (out of circuit)?

This suspect MPU board could have some slight resistive short (commonly caused by corrosion) between switch return lines.

Grab your multimeter and set it to read resistance. If your meter isn't auto-ranging set it to 200k ohms scale.

With the MPU board cold, machine OFF and J2 and J3 disconnected, measure the resistance across the following pins - the readings should all be around 114k ohms:

J2 pin 1 to pin 2 =
J2 pin 2 to pin 3 =
J2 pin 3 to pin 4 =
J2 pin 4 to pin 5 =

J2 pin 8 to pin 9 =
J2 pin 9 to pin 10 =
J2 pin 10 to pin 11 =
J2 pin 11 to pin 12 =
J2 pin 12 to pin 13 =
J2 pin 13 to pin 14 =
J2 pin 14 to pin 15 =

Those readings all looks fine to me.
Install a new capacitor on that Miss January standup target like CactusJack said and see what happens.