Would you package the textures with the map itself, or is it impossible from the point of how MBG works?
Also, I don't know how the .cs files work, so I borrowed one from the Bedroom map to test it. That may be another error.
My lack in knowledge in packaging may require some patching so I can port maps from MBG correctly. (I may release them later given they work)
Quick offtopic: This is a new account I made, because my other one was inactive in terms I barley used it. So I made this one, to go with my new name in Blockland.