FT 036 switches and old CW-80

Reverse the connections, common wire from Accessory U(Acc output) on the transformer goes to AUX IN on the switch. You don't need the connection to the AUX GND, it's already made through the switch and outside rails to the Acc red/"A" post, which is common to the track red/"A" post.

Generally, yes. You have described the connections properly. You might experience some strange behavior with the whistle/bell buttons.

Rob, thank you. 

Regarding the strange behaviour of the whistle/bell, yes I have already experienced it and was aware of it as I had read numerous posts about the qwirky CW-80.  I have an older Lionel GP-38 and the when wired Track A to center rail, the duration for the whistle/bell sound for the loco was controllable by the length the button was depressed.  Now with the Track U to center, the bell is sounds for a fixed duration (several seconds) no matter if the bell button is just depressed for a fraction of a second. 

Again thanks.

Because you are using the "A" terminal as common, where the bias is introduced(the "high side"), you may get activation on the other track as well. Maybe, maybe not, or sporadic results.