No wire cutting, just slashed an accessory wire to hook the mirror wire. Ground wire was fitted in a screw. I was too afraid of opening up panels and hooking these wires, but a fellow Pakwheeler got it installed in his Ciaz and Grande and running fine. He referred me to his electrition in Saddar, Pindi who is an expert and handled everything meticulously, not forcing anything and taking his time for a neat and safe installation.
PS: Yes Aliexpress link posted above