That makes a lot of sense. I was just trying to add some cool top down parallax effects to add more of a 3d feel in addition to the 3d lighting. It's very impressive what this light system can do for 2d graphics. I did not want to touch 3D in GML, so I'll pass on figuring any of that out, ha!
"Some other things to note, when drawing normal maps I use the alpha channel to encode the emissive value of that pixel. So, you would actually want to draw in 0 alpha if there would be no emissive. That can be done for the entire normal map sprite, or per-pixel in the normal map itself."
I was just using the alpha setup from the other object normal draw events, which uses LE_NORMAL_ANGLE for the draw events in the events I listed. I could always have it send the emissive variable instead.