Hey Michael,
I am happy to share my hands to solve your problem.
TextureSettings are used for cooking textures while packaging, and it is not common to modify texture2d after loading due to performance and platform dependence. So instead of looking to use texture setting in runtime, I would like to know your specific requirements.
Also, it is hard for me to find a reason for doing mip-gen or texture group, if we know all the textures are used for UI. Having material with the textures on UI widgets and doing some process is the way we may have to do it in UE.
Cheers,