Maybe you can try post process volumes and ambient cubemaps instead of skylights. You have the same controls of a skylight, but with the added bonus of being able to change the values based off of you distance between volumes. And I do believe you can animate the values in Blueprint. Yes, you will have to have a generic cubemap for lighting, and the same cubemap may not work in different situations (like indoors), but it sure as heck beats environment colors and skylights in UDK (read: ONE color ambient light).