This is not a step by step instructional guide on how to fix the textures, but an explanation for why the texture for the Cremator's eyes & filter is broken.

The models UVs are incompatible with the textures in the pack, and tries to layer it based off of a UV pattern that doesn't exist, resulting in the texture error.

The model from this addon (https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3511207710) *should* have a properly compiled model that contains the appropriate UV for how the eye texture is set up in the Give & Retrieve pack. I have not tested this myself, but by using a third party tool (that is not gmpublisher, which you will still need to extract the base code & structure) you will be able to decompile the model I linked, modify the texture sources in each model file so the custom textures appear, and finally recompile.

***This does not account for any animations that the Give & Retrieve model has that the linked model doesn't, so if any animation errors occur, then animations are missing.***

Edit: Remember to rename the recompiled model so that it actually shows up in game, etc etc...