So today I took a look into the Mac/Linux user's issue with missing textures. The solution is renaming the texture files from Uppercase to lowercase.
I have finally gotten around to testing a rename of a texture
(British_5thWIR to british_5thwir WIR = West India Regiment acronym) for an example. In-game no error pop-up of RGL error. I do need to know if numbers can cause the texture errors as well, so besides capital letters keep your eyes on the lookout for that. I will plan a Mac/Linux version with lowercase texture names especially if Mac/Linux users are unable to change to lowercase.