When the driver board was removed to replace BR3, were the header pins reflowed with Solder ?

J107 in particular. This is where the Solenoid voltage to the coils is sourced.

Pin 2 - Ball, Release, autoplunger, gun launch, top right popper, gun popper, knocker, trap door high
Pin 1 - Top left popper, left diverter, right loop gate
Pin 3 - Slings, pop bumper, left popper, ramp diverter, trap door hold

In the solenoid test, isolate the group of solenoids.

You also have fuses relating to the solenoids F103-F105. If you can isolate the solenoids to the fuses as per page 1-47 of the manual, then you may find a fuse that could be the problem. Could also be the fuse holder.

Flippers - check the Fliptronics board. Are the fuses ok ?