[BScout]

HD Native card/HDX can see up to 64 channels in/out (up to that depending on what interfaces you have hooked up to the minidigilink on the first card only -- HDX's case) as CoreAudio/ASIO. Written clearly on Avid's website.

Pro Tools does not use CoreAudio/ASIO to talk to Native cards/thunderbolt or HDX. There is a separate service for other programs to talk to them that presents Avid hardware as a CoreAudo device. You can even kill that service to eliminate other DAWs/programs from being able to talk to the HD Native/HDX card over CoreAudio/ASIO and Pro Tools will continue to work. So Pro Tools is never using the CoreAudio driver to talk to these devices. For that reason, it has better performance under ProTools than other DAWs talking to it via CoreAudio/ASIO.

You are only running into the first hurdle with the digilink license alert. You can only use Ultimate with HD Native cards/TB/interfaces. This is already well written on Avid's website.