I accidentally connected some CL2 drivers backwards

Try one connected properly.  You're only risking a 5 cent LED to see if they still work.  Personally, when a component has been connected incorrectly with power, I normally just pitch it.

Depends on how long you had the CL2 hooked up backwards.  When backwards, the CL2 looks like a diode which would mean huge current flowing into the LED through that diode...unclear what caused the flickering but if the CL2 diode did not get damaged the chip itself may be unscathed.  From the CL2 datasheet:

That's a pretty small diode in the CL2, but the LED "fuse" may have saved it.

I wound up replacing everything.  The leads on the CL2 were too fragile for reuse, and I broke off the leads on the bridge rectifier.

I think the flickering was related to picking up power from the brush well.  With the original grain of wheat lamps, they only lit in forward operation.  Reverse operation still gave voltage, but not enough to light the lamps.  The LED flickering showed up when cycling to reverse operation.  When I metered it, it was showing less than 4V in reverse, so not enough for the CL2.  I wound up pulling power from the center pickups, and no flickering.  Downside is the ditch lights are always on, but I'm OK with it that way.

Thanks again for all the advice you folks always share.

Chris