Ah, yes. I suspected it might be on piles, judging by the in-line holes in one of the pics. (thought they could have been removed vegetation though).
The tricky part with building on piles will be sound-proofing the floor, but that also depends on what level of "containment" you require. It can be done though as long as floor, walls, roof go in as separate components. If it's a fully assembled pre-fab unit being set in place with a crane, that's a different story.
Both my studios were on slabs (one in a garage, one in house) so I thankfully didn't need to address that issue.
I'll enjoy watching this thread as much as guitar build!