I had a major breakthrough today, I got the LionChief remote to send bell and horn commands to a legacy locomotive. If I didn't have to leave I could have finished getting the other functions running too!!
Work in progress video here: https://youtu.be/9tPro7mHm8A
Full control of TMCC functions is a work in progress. Legacy features might be possible after that.
@Landsteiner I know you were asking about this feature.