Cut it off and replace with new armaflex. Just measure the pipe sizes and order two pieces one for small and large line. They usually come in 6 foot lengths. Make sure you get the pre split covers. The pre split has a sticky tape on it and you just peel the plastic off and it seals it around the...
Extra mig gun tips, mig pliers or you can just use wire cutters. Grinder with flap disk or a wire brush to clean metal. Weld clean metal, burning paint or galvanized metal fumes are poisonous. Check YouTube for tips and go for it.
Hyper heat is the Mitsubishi super cold weather line. Mini splits loose heating ability as the outdoor air gets colder. Hyper heat line is designed to heat into the single digits, if I remember correctly, at close to full capacity.