I would not keep fancy goldies in an outdoor pond, but the commons, comets, and shubunkins would be okay as long as the pond does not freeze solid. You would need to make sure that it is deep enough that they have swimming room under the ice, and that an area is kept open for gas exchange on the surface. Dr's Foster and Smith has pond de-icers that would work to keep an area open. It would basically depend on what type of pond you were going to do, where it is located in your yard, how deep/large you can make it, etc. If you are worried about snow building up on the pond, then maybe some type of framework gazebo-like structure over it that can be covered with a tarp or something to protect it from too much snow. You would need to have it go probably 3 feet deep (below the soil) to help insulate it. That way the water at the bottom of the pond would stay a bit warmer during the winter and cooler during the summer. If you had a de-icer as well, then it would be just fine. The de-icer would help to keep at least a small area from freezing over so oxygen can get into the water in that area.
The lionhead and the oranda probably would not do well out in the pond at all. The fantail would probably do fine from late spring through the summer to fall, but would probably need to be brought in for the winter. The common would do fine outside year round. How big are they? The three fancies should be fine in a 55 gallon tank. It would be best to move them to the larger tank as soon as possible. At least by the time they are 1.5 - 2 inches long. As they get bigger, the common may pick on your fancies. The common is a faster swimmer, and can grow larger than the fancies, and may start bullying them.
Your pond would have to be really deep to keep from freezing solid and keeping it aerated all winter would be tough. I use a stock tank heater to keep the surface of my pond open in the winter but we rarely see any temps below 10. If you don't want to use an aquarium for winter housing, a stock tank in a garage would work, as long as the water doesn't freeze the fish would be fine. My fish are currently in the swimming pool while the pond is rebuilt.
I also keep some goldies for summer.. I like to have a rain barrel and I got them when they were 1" long and stuck them in the barrel to eat mosquito larvae.. that was two years ago and they are now 8" long. I have three of them surviving the winter in a 25 gallon tank with weekly 50% water changes. I bet they are looking forward to spring and their to gallon barrel.
Mine lived outside until after the 2nd frost. They don't seem to mind cold water so long as it isn't solid.
I have heard of people around here throwing a waterproof 100 watt trouble light and an aerator in a pond to keep it liquid underneath with a surface hole. I haven't actually seen that though.
As long as we are on the subject.. does anyone have any suggestions for a clear sided water barrel?