Do I need to remove the entire mirror assembly to install this glass?

Yes, you'll need to disassemble the mirror housing to swap the glass. The glass itself uses factory attachment points — no new fasteners or adhesive needed once the mirror comes off the vehicle.

Will this glass fit if my mirror housing is cracked or damaged?

This is the glass lens only. If your mirror housing is cracked, you'll need to address that separately — the new glass won't seal properly against a compromised frame.

Does this come with the mirror backing or just the clear lens?

This is the glass lens only. If you need the backing plate or mounting bracket, those are sold separately.