From Frank Cannavale:
Note that many of the 74-75 Imperial's standard features were optional in the New Yorker Brougham, such as Auto Temp. Others such as 4 wheel disk brakes, were not available. So, if you are pulling a NYB wiring harness, check for ATC and other "options."
Note some of the harnesses are separate, so there actually may be three or more different harnesses behind the dash. You'll need to get all of them.
St. Regis option package was available on the 74-77 (78?) NYB 2-door.
Basically it was a dress-up package with various trim pieces. The big addition was a padded landau vinyl roof.
From Darryl:St Regis was an edition of the New Yorker, better than the base, not quite the Brougham. I have a 77 Chrysler catalog, and it appears that it added leather and auto-temp, but there is not a written description to back this in it...