Would it be possible to define protection on hat stands for server/admins/players so other players can't change or unequip hats? Currently, anyone can place down a hat stand and an another player could modify the hat stand. I am creating an in-game hat store and want to showcase these hats but players could modify the stands.

Closing all issues as Hats has been rewritten from the ground up and the old mod for a long time now was no longer supported.. I'm sorry I wasn't able to address your issue. If you're still playing modded Minecraft, consider checking out Hats for 1.16.5+.