ALL'S WELL THAT ENDS WELL!!!
After 20 miles of driving, visiting 2 Auto Zone and 3 Advanced Auto Parts stores, and $18 poorer, I finally found a pair of red tail light units to match those on the trailer and bought the flat-4 connector I needed. I replaced the amber covers on the Squidget with the red ones off these units.
I wired up my tail lights and both turn signals from the dealer supplied flat-4 connector pigtail to the round 6-wire connector already on the truck, so that the two trailer turn signal lights will work through the trailer relays to flash and brake. I left the brake light wire connected to the truck wiring and my ground wire on the frame, as those worked fine. The original trailer brake lights will work through this separate wire. Should the ground ever go bad, I can switch it to the flat-4 connector ground.
Now, the trailer has four red lights that light up when the brakes are applied, and only one on each side flash for turn or emergency flashers. These are the two that were amber.
I haven't changed the boat trailer light bar, so it still has the brake/flashing amber lights. I'll probably leave them as is. The truck lights can be seen around the boat anyway.
IT ALWAYS HELPS TO HAVE YOUR SUGGESTIONS AND COMMENTS TO HELP COME TO A SUCCESSFUL CONCLUSION...THANKS.