Your easiest connection will be a stainless braided 1/4" compression supply tube.
Once you start cutting plastic pipe, you could get yourself in trouble.
I know of a PEX like supply line for a European dishwasher, that when cut and spliced, came apart later and caused $100,000 worth of damage to a home.
Most places that sell refrigerators will not connect them for that very reason. They don't want the liability.