I'm trying to create custom markers, but add 2 map layers.
Essentially trying to combine this: https://www.mapbox.com/mapbox-gl-js/example/custom-marker-icons/
With this: https://www.mapbox.com/mapbox-gl-js/example/toggle-layers/
How do I specify my customized markers, but assign them to 2 layers?
Markers don't exist within the map's Style, so they don't live within Layers either. They sit on top of the map, effectively within a single "layer" (but not actually a Layer).
So if you're trying to find a way to hide or show groups of markers in a single action, you'll have to find another way to do that.
Alternatively, if you really want your markers within Layers, you should create Symbol Layers with icons, not markers.
