Do it the other way around. Reference the light scene into the xgen one. Thats the safest workaround. If thats not possible reference the xgen one with namespaces into the light scene.
That was just the wind xgen modifier + colliders. But the right way to get a believable simulation is dynamic nhair curves for the guides (or animguide modifier) and xgen colliders for the single fibers.
Great to see XGen hair, I started teaching XGen alembic cache to UE5 this year and it felt like I was jumping the gun so its great to see it coming into use. I also noticed it in FIFA 23 I Iove this shot :)
I enjoy using Yeti over Xgen as a newbie in 3D grooming, but I don't know if hair created in Yeti can be imported into Marmoset like how Xgen hair can be converted to polygons. Or at the very least, can we use Yeti to make hair cards?