NI was never supporting Sonar. They are sending a bunch of notes on channel 1 and may be reply on "Are you Mackie?" with proper "Yes, I am...". That is what "Transport control" for Sonar and other unsupported hosts means in the table.
There is no required function in ACT to implement track selection and focus. Cakewalk has "hacked" something for Console 1, but I guess on VST extension level, not in ACT.
In general, Cakewalk ignore surfaces, surface producers ignore Cakewalk.