Thanks.
Just posting some info from my experiements to see if I can shed any light that might help:
I can get the KK keyboard to respond to instances of KK hosted in VEP. The problem as I see it is that the communication is then between VEP and the KK keyboard.
So although you can play and record from the keyboard inside your DAW, the actual interaction between the hardware controls and the Komplete Kontrol happens outside the DAW.
So Track Focus can no longer work inside the DAW. There is a workaround to use the hardware to choose which instance of KK applies to the track you are on, but this is impractical as it changes window focus to VEP (which in my case is maximised and covers my DAW making me have to reselect the DAW afterwards).
I do know the KK software makes use of some kind of OSC template to communicate (at least with Logic) and there is a control surface installed that uses ports that are numbers rather than physical ports.
https://support.native-instruments.com/hc/en-us/articles/210279905-Setting-Up-Apple-Logic-X-for-KOMPLETE-KONTROL
Due to the way KK software works you have to create a separate Instance in VEP for each KK instance as you cannot use Kontakt Multis.
Maybe the key might be having the instance focus in VEP switch when you switch track in the DAW?
By the way I tried using a KK instance in my DAW with a VEP plugin inside it connected to an instance of Kontakt in a VEP rack. It connected but none of the feedback gets sent to the KK keyboard such as the Lightguide and all the knobs just display "Parameter 001", "Parameter 002" etc.
I can use the VEP automation mapping to set up mapping to Kontakt parameters, but the Lightguide will not respond. So there is a lack of passthrough MIDI communication to VEP.