This doesn’t seem possible… or at least I can’t figure it out. I need the emissive to bake into the lightmap. Let me know if that’s possible and I’m just missing it… and if not, how to request that feature.
This script worked for me in LWRP.
https://support.unity3d.com/hc/en-us/articles/214718843-My-Emissive-material-shader-does-not-appear-in-the-Lightmap-