Hi GreenLeo,
Yes - the Isabellina HPA will use the Isabella headphone amplifier board (which is the same as used in the Amphora).
The Isabellina dac is already a fantastic sounding source, and feeding this into the same board that we use in the Amphora will be an amazing pairing (I already heard the Isabella dac + Amphora combo, so I know how well they sound together!). With the Isabellina HPA, it is all in one enclosure (no interconnects or RCA jacks in the path) and powered by a high-current SLA battery. So expect great things!
I also might want to experiment with the wiring that Ken is using in the Amphora SE models because it sounds so good!
I'll keep you all posted,
Vinnie