Can you substitute shortening for oil in a cake mix?
You could substitute shortening for oil in a cake mix, but it is not recommended. The resulting cake made with shortening will have a noticeably different texture and mouthfeel. Yes you Can. Shortening.. or Hydrogenated Oil is basically poison anyways.
Yes, but the results might not be the same. Liquid oil and solid shortening have slightly different properties. You might need to use slightly less oil for similar results, when "creaming" shortening the results do not work for oil, but this step would be dispensed with when using oil. Butter or lard, which shortening was designed to replace, will get the same results as shortening.