Neat project. One thing I don't see covered: is everything going to be statically linked like it is on Alpine Linux? Is statically linking libc advisable on a NetBSD kernel? I know (unlike Linux) the FreeBSD kernel ABI can change every major release, but I'm not familiar with NetBSD's approach.
NetBSD retains the old ABI as well if anything changes to a syscall.
Alpine Linux is not statically linked. It provides a musl environment which makes it easy to statically link your own builds, but software shipped as part of the distro is usually dynamically linked.