Little Giant pump would work, it is also runs in very low temp.

Head pressure is the issue, maybe two pumps for a very long run.

Home depot and buy copper pipe to make heat exchanger that sits at the bottom of the well but...

The run is long and will inherently lose temperature if it is not insulated. Thus making the well trip useless.

Just build a box outside the wall where you are want to put the PC, put the radiator, fans and pumps in it.