I see what you’re saying now, yes. Data layers are a new feature, UE5_EA, so you could easily bake lightmaps and keep them on one layer, and the dynamic maps on another. Spawning, game logic, lights and FX and more can live on a third data layer, and should be compatible with both. They’re fast to swap at load or even run time, so it would be well suited to multiplayer.
And on your concerns, ghosting is a problem, but it truly depends on the size of your map and budget. You can tell lumen to flush history faster, but that comes at either the cost of noise or a performance hit. If they’re reasonably small maps, you should be able to crank things relatively far. I understand the aesthetic you’re going for, and I think it’s entirely achievable with lumen. Even though they tell you not to depend on it, lumen emissive lighting is one of my favorite features, as it lets you easily and creatively light a scene however you want.