Are creams that are not removed by water except with soap considered a barrier to Wudu', and is it permissible to eat food if it contained alcohol that has evaporated, and is it obligatory to verify the type of alcohol used in its production?

The criterion for an interposing barrier that prevents water from reaching the skin is that it must have a tangible mass. If the cream forms an insulating layer that prevents water from reaching the skin, it must be removed before ablution. There is no need to investigate its ingredients. However, if one is certain that the cream contains alcohol, and one follows an opinion that deems alcohol impure, and the alcohol has not undergone استحالة (chemical transformation) within a pure liquid, then its use must be avoided. But for someone who follows an opinion that deems alcohol pure, or if the alcohol is minimal and has undergone استحالة within a pure liquid, then there is no harm in using it.