1. With the Probox I can still use the audio on the D8b for input into Protools via my D8b ADAT lightpipe interface, If not can I use a parallel printer A/B box to switch between Probox (DAW Controller) and Mackie audio (Tracking) as normal?
YES !! It's possible.
Follow this link to see the video recorded by Alain Iandry: https://www.youtube.com/watch?v=JMJuh-tPBzw
Cheers