I am also doing realtime/mobile VR stuff and used RedShift for light map baking in Houdini. But the downside is, that these maps have to be used in the materials, at least from what I've learned. Maybe there is a way to feed these maps into the actual UE lightmap channel, but I haven't figured this out yet.
In my case using materials was still okay, because I was processing a lot of CAD Data and I was also just looking for some AO and Contact Shadows to get an overall smooth feeling for all objects. The reason why I used redshift/ external baking is because I was also slicing the cad data and I need a proper interior lighting which would have been even trickier with UE light baking...
You get an idea from this Video:https://twitter.com/SchuchFelix/status/1447596342189117447?t=MHOLyihFLDnzASwoArQ0dg&s=19
I built a clustering SOP network to combine and pack objects using the same materials in order to reduce draw calls and then baked AO maps using TOPs for each material cluster. It was a bit tricky to set it up, but once it worked. I was able apply this to all CAD files and I had 5-10 textures with texture information for all objects. Instead of TOPs you could also use the frame range for batch baking.
Since the amount of CAD I am handling right now increased a lot, I am currently trying to stay in UE for baking and I am just using Houdini for an efficient lightmap UV packing.
Maybe this helps and let me know if you have any questions.