BuddyPress.org

I have read all that but none of those scenarios seem to match mine.

This sounds about right: “I’ve built a completely custom WordPress theme and BuddyPress theme”

But like I said, when I move /wp-content/bp-themes/themename to /wp-content/themes/themename per the instructions here: https://codex.buddypress.org/how-to-guides/upgrading-a-buddypress-1-0-theme-for-buddypress-1-1/ that doesn’t do it either.

Is it because my bp theme doesn’t have a parent/child relationship?

The entire BP theme is /wp-content/bp-themes/themename