While I haven't tried crochet, I have tried building my own RPi-B+ image. You mention in your guide that you'll post updates "when you have something", and judging by your post it seems you have.
Since I had difficulties compiling the zfs (and one other, which I don't recall) module, I'm wondering if you'd care to share your experience in your guide?
Kudos to your very well thoughtout and thorough guide.