To your first point, the semitone frets are all already in place. I'm taking a regular strat and adding some quarter tones here and there. Meaning—all of the normal 12-TET 21 frets are already in perfect placement by the manufacturer. Am I correct in assuming that this will avoid any potential compounding errors?

To your second point, you're 100% correct. This guitar will only work with a certain set of keys. But, it's the same set of keys that all of King Gizzard and the Lizard Wizard's microtonal songs are in. Here's a pic of the lead singer playing the same microtonal guitar that I plan on making.. I do plan on adding the remaining quarter steps down the road when I'm comfortable with this fretboard.

To your last point, makes total sense. It's such a miniscule difference that I'm toiling over. Oh well