I’m currently trying to create a gfx for my friend that involves their friend.
Unfortunately, I’m having trouble with the hair and glasses texture, aswell as their friend having korblox. I’m currently using a blocky rig and have no idea what I did wrong.
Blender
In-game/Roblox Studio
I’ve already tried looking for some solutions, however, have unfortunately found none, obviously.
Did you try taking the texture from the website and put the texture in the hair+glasses.
Go to the website, search for the item(The hair and the glasses), get it inside the explorer, and change the texture to the real texture from the website. 
Changing the TextureId will maybe help you.
How can I take the texture from the website?
This is due to the rig you are using, which is “PaintRigV3.”
The rig does not support packages, and will opt to the default ROBLOX Package by default. You’d need to make the rig yourself, or find a rig that does support the Korblox Package.
Last time I checked however, the only rigs I am aware that is publically known and avalible, is the Default, 3.0, and 2.0 package rigs.
To take the texture from the website is used by the “contents” tab where I think does no longer exists. To access the texture from the website you will have to download a third-party extension like Roblox BTR that handles items features like getting the texture.
The safest way is to get the item inside the roblox studio go into “SpecialMesh” inside the wearable item.
In explorer, you can get the item’s textures and specifically from the player “asi_a” try finding the player, dummy that is named “asi_a” and expand until you find the mesh and textureId.
In the first picture it just automatically removed the package.
@frogzster Maybe try making it R6(default) and no packages(just remove the leg).
I already mentioned this
The Korblox Package will not work on your rig.
For the korblox issue just pose the character and when your done delete the leg and add in the korblox leg