To answer my own question—and to actually help other people with similar use cases—I read about uv's build process and dependency locking. It does not appear to be able to lock dependencies for build distributions (wheels).

https://docs.astral.sh/uv/concepts/projects/build/

https://docs.astral.sh/uv/pip/compile/

However, it does mention that Python supports multiple build systems, which I didn't know, so this hasn't been a complete waste of my time.

Thanks!