How can I remove the brick that jets out from my fireplace to make it a all flat. Ideally I would like to remove that and put drywall over the other bricks and then putting tile around the firebox and then put a mantel that goes all the way across the front of the fireplace. Any ideas or suggestions would be greatly appreciated!

Use a wet diamond blade saw or a dry saw. Only other choice is to whack away. Don't put drywall on the brick face directly above the firebox, it must be, I believe, 18" clearance to a combustible surface. Use hardie or backer board above the opening.