I have been using a small pancake compressor without any issues. If your compressor is too weak you can always turn the little dragon off and let it catch up no need to break the bank on a shop compressor
I am also interested in any information that could help convince the building inspector that Aircrete is a sound and reliable building material. We have the New Madrid fault line and they're very strict on seismic regulations.
I intend to use hydronic radiant floor heat using PEX piping on some foamcrete slabs I'm planning.
Do you intend to just stick with concrete floors, or are you going to be installing a different flooring material over it? If you're going to use a different flooring material, you can install a floating floor over the existing slab. Lots of systems designed for that purpose.
If you're just planning on sticking with concrete/foamcrete floors, I would think that the best approach would be to pour the foamcrete pad, lay down the grid for the radiant system, and then do a pour of self-leveling concrete over the top of that, which you can dye/stain/seal/epoxy however you want (this is my plan).
Another benefit of this is that you can come back and add this at any time, so if budget constraints prevent you from adding it during the initial construction phase, it's no big deal. Add it when budget allows.
And, of course, yet another benefit of the foamcrete slab is that it will serve as an insulator between the radiant floor heat source, and the ground, significantly reducing ground loss. Win/win/win.