Not once has myself, nor anyone else stated the original creators of the mods own the content created. It may be within taleworlds legal rights to use the mods as they desire because it is an extension of the code they used to create the original product, but they did not create the content personally.
You are morally obliged to seek permission and give credit to the people who did create the content. As stated previously, permission should have been seeked before you released any of there work, do not wait until your deceit is stated publicly.