Would it be possible to add the vapor effect( ignoring the ice for now) to a smaller part, i.e. not an engine? That way we could place the part near the base of the engine and have the effect that way, or at the side of a tank or launchtower to get the Tank boiloff effect. I'm new to modifying ksp so i have no idea if this is possible or not. But in my opinion it would be the "most compatible" way of adding the effect without having to edit every engine and tank config.