As the HDSPe AES is an interface card with TotalMix FX I assume, that this is your main card in the PC.
Simply use this card as clock master.

Then connect the ADI-2 Pro via AES and configure it to get clock via AES: Options -> Clock -> Clock Source: AES
In the state overview check the sync status from AES.

The ADI-2 Pro refreshes any incoming clock signal and takes finally its own internal clock for the D/A conversion.
So there is no reason to make the ADI-2 Pro clock master.
In your setup it will be better to take the HDSPe AES as primary interface which sets the clock for the rest.

On the ADI-2 Pro you can additionally use the remap-key function to switch between phones and speakers like described here in my blog: https://www.tonstudio-forum.de/blog/ind … up-EN-DE/. This way I use it and it works very comfortably.