Congrats on the new house and on seeing a beautiful pond in your future.
Being in the shade shouldn't have a negative effect on a pond. It will help limit algae and water evaporation for one thing. It will also slow the growth of any water
plants you use...as often water
plants are almost invasive with the speed in which they multiply.
As far as fish go...your pond needs to be at least 3 feet deep. If the pond is, say, 8 feet long, 4 feet wide and 3 feet deep it will be about 700 gallons. You can hold quite a few goldfish in there (not kois though.) 35-70 common goldies can comfortably live there...although I would suggest starting with half a dozen and letting them fill out the rest of the space...which they will happily do in the
spring.
You can find various heating appliances such as large capacity fish tank heaters or bird bath heaters, that can keep the fish alive in the winter. If not, then a large rubber maid tub, in a stable temperature, can make a good winter home for them.
Make sure you also treat the water for chloramines/chlorine. Many people mistakenly believe that letting the water sit will allow these to evaporate out. This is true of chlorine because it is volitile and unstable. Chloramine is far more stable, and thus widely used in water treatment
plants now. It does not evaporate out ever. You can get a large bottle of pond conditioner at your favorite home repair store for $3-4.