Preservative refers to a substance that inhibits spoilage, decay, discoloration or other drops in quality.
It’s one way to increase shelf life.

A stabilizer isn’t a preservative because oil separation doesn’t impact quality, shelf life or anything like that.

Citation needed. Most of the emulsifiers in ice cream are simply different sticky carbohydrates. Usually beans.

Studies show that there might be an impact that contributes to risk factors leading to an increased risk of certain metabolic disorders. This means that we need more study, not that there’s anything that warrants changes in behavior or saying anything definitive.