Hey Tim. Great thread! This thread somehow passed me by until now, just finished reading the whole thing. Whilst I love all the builds here in LC I particularly enjoy the "first builds" as they tend to be more detailed and more useful for beginners like me (also trying to finish off my first build, over 2.5 years in!).
It shows that most people with a reasonable amount of common sense and an ability to logically follow a process can build their own bass.
Good luck with the fret levelling, it's really not that hard, the hardest bits are behind you already.
One thing I didn't see whether you had is a fretboard protector, (thin strip of metal with a slot in it) or make sure you mask off the fretboard well to avoid marking it. And it's easy enough to make a long flat beam from wood with some abrasive glued to it, I personally think if it's covering all the frets at once that is the most foolproof way to get them all level.