All of a sudden my Kumos HA is showing up on Legacy. I went into the Legacy wardrobe and hit "wear" again on my current HA, but it's not appearing. Unfortunately, I'm still unable to migrate my HAs accurately into the new wardrobe, and the body parts I removed in the new wardrobe are still showing up when my HA is around the site.

Have you 'opted in' to the Kumos wardrobe? If so, it'll show that avatar everywhere while you're opted in. Clicking wear on the legacy wardrobe won't do anything to change that. If you go to https://kumos.subeta.net/wardrobe you can "switch to the legacy version" which should change your avatar back on both sites.

Thank you so much for the solution! What a silly thing for me to miss!