Anti-freezing tape is installed in pipe without problems. Wire to submersibles is wet all the time.
I would use wet-rated. Much of the single strand wire available is THHN/THWN/MTW. Temperature will certainly not be an issue in the pipe. You want one piece if possible. You might run the last 20 ft through copper and the ground it at the delivery end by attaching it to the equipment ground at the electrical source point.
To reduce pressure drop, I would use the smallest flow and not use twisted wires.
The electrical fitting will be non-standard. There may be something available. My first thought would be to run each wire through a 1/4 fitting with some kind of non-metallic packing. Most of the plastic fittings that I have seen are rated at 100 psi, but you might find some that would handle 120 psi.