Not sure if this will help, but it might be worth a try. The ZW-C does communicate with Legacy, you can program it to control the handle outputs via the Cab-2 by assigned track numbers. B and C come up where the handles are set, and A and D come up at 0 no matter where the handles are set.
Try powering on the ZW-C first, wait a couple of seconds, the power on the TMCC base.
I realize you are running TMCC not Legacy, so I am not sure if it behaves the same.