Does this come with the mirror backing plate or just the glass?

Just the glass lens. You'll reuse your existing mirror backing and mounting hardware from your vehicle.

Will this install without removing the entire mirror assembly from the door?

Yes. The glass pops out from the front — no need to disconnect wiring or take the whole mirror off. Clips release from the inside of the backing plate.

Is this heated glass if my vehicle has heated mirrors?

Mounting method not confirmed on this listing — verify your mirror type (heated or non-heated) before ordering to ensure compatibility with your backing plate.