Saved skins are always prioritized over player skins, but as of version 2.0.2, this behavior can be modified by adding the -o flag at the end of the command. That way, you can still use the online skin of a player, even if there is a saved skin of the same name. I hope this fixes your issue.

Thank you for taking the time to review the plugin.

As of right now, this is only available as a Spigot plugin. However, it is open source and a lot of the code is based on Mojang's NMS code, which wouldn't change between platforms, depending on which mappings are used. I do understand the appeal of using Forge or Fabric. That being said, I do not have any experience with Forge or Fabric development myself, so its not high on my priority list. If any other developer wants to take the code and adapt it for another platform, I encourage them to do so.

Thanks for the review!

To answer your question, skins don't have names until you give them names. When you run /skin set <your-name> <player>, you are setting your skin to the skin that the other player currently has. For example you would run /skin set <your-name> jeb_ to get jeb_'s skin. You can give a skin a name when you save it. type /skin save <your-name> followed by whatever you want the skin to be named. For example, /skin save <your-name> Jeb-saved, or whatever else you may want. That will save the skin's texture to the config file. After that you can use /skin set <your-name> Jeb-saved to set your skin to that saved skin. All of the saved skins will be listed in the config file, as well as in the tab completer for /skin set, /skin save, /skin remove, and /skin setdefault.