And the adventure continues... (the following times are for a simple scene with a few meshes and the epic mannequin)
Modular shadows with Stationary Light work with Mobile HDR and look great... but horrible framerate(14fps).
CSM shadows with Stationary Light and Mobile HDR have better frame rate (40FPS), but still look CSM poor.
Static Directional Light NO SHADOWS WITH Mobile HDR (56 fps)
Static Directional Light NO SHADOWS NO Mobile HDR (72 fps)
Stationary Directional Light CSM SHADOWS NO Mobile HDR (72 fps)
The moral of the story so far is Mobile HDR pretty much tanks the framerate.
CSM shadows look poor but probably better than nothing.