This might be possible with UE4’s built in reflection captures, I noticed an unusual phenomenon where reflection captures will capture static lights but only when the reflection capture is first dragged into the level. Once you’ve built the lighting/captures again the light disappears from the reflection cubemap.
I will say however that this is usually a non-issue because lightsources rarely exist on their own except as fill lights (where you DON’T want them to show up in reflection captures).
99% of the time they’re attached to a mesh with an emissive material that will get captured in reflections with correct bloom and all. So if you really want your static light to show up in reflection captures just put a sphere around it with an emissive material.