I've had a lot of water intrusion in a home I purchased that was covered up. I only noticed after starting renovation of the fireplace surround that turned into going down a rabbit hole of a rusted out firebox, separation of the surround, sagging floor, water intrusion, and crumbling mortar. I'm at a point now where I'm unsure of what to do but have a vision of getting a wood burning stove to place in the fireplace after rebuild. Does anyone have any inputs or direction of what to do? Attached are pictures for reference.