My thought is that you're going to end up with something thin and bitter as hell. I'd up the OG to at least 1.060 and it'd make a better beer at closer to 1.070. Black IPA should be dark-malty instead of burnt-roast flavor like a stout. Maybe adding a good portion of Munich or Amber LME would bring some balance to all that Chocolate roast.
Also, in my experience, Mosaic for bittering at 60 is harsh as hell. Even your 30 minute addition is a lot. I'd consider using something more smoothe and neutral. Your Amarillo might be nice, though I don't think you should take it out of your dry-hop. If you can get your hands on some Warrior, it makes a great bittering hop for NW styles.
