We've added a new feature to the latest 16.5 builds of the plugin. It introduces two new attributes - unreal_split_instances and unreal_instance_color:
unreal_split_instances means generate a UStaticMeshComponent for each instance, when you have Packed Geos. (By default you get one UInstanceStaticMeshComponent per mesh). In addition, the unreal_instance_color is an override on the vertex colors for each instance. This is a per-component color, not per-mesh. This can be used to provide variations to scattered instances. For example I can scatter 20 instances of 4 kinds of rocks on a surface, where each instance has a random color. I can then use that color in the ue4 material to provide some further variation to the instances.
Let us know what you think.