You're on Java, right ? Basically, allowing non-official version to join your server will disable all skins and capes. In your server options, you should have this somewhere :
"online_mode=false"
Replace 'false' with 'true' and re-open the server.
Yeah, textures on models can be a hassle... If you see a purple texture instead of what should be yours, it's probably because your folder tree isn't EXACTLY how the game wants you to do. Pretty annoying. I'm sure you'll find how
Make sure it's on in-game. Also, if you make modifications, you have to reload it by pressing F3+T
I would suggest you use an existing pack to see how it works. Also! You can use /version while in-game to see what 'pack_version' you need to use in your pack's .mcmeta file.
