What is the ruling on buying and consuming foods (such as yogurt, biscuits, chocolate, and ice cream) that contain flavorings or aromatic additives, without certainty of the presence of alcohol in them, in non-Muslim countries?

The fundamental principle regarding things is permissibility until prohibition is proven. Therefore, there is no objection to consuming any food or drink unless it is proven that it has been mixed with something forbidden, such as alcohol or pork. If you are certain or highly suspect that the food contains something forbidden, then it is not permissible to buy or eat it.