I know you're set on moving your fish, and really that's your choice. But I can tell you, here in the Chicagoland area, ponds are deep enough for overwintering fish at only 24 inches deep. You need a way to keep an opening in the ice, but other than that, pond fish are fine in frozen ponds.
Mainly people would encourage you to leave your fish in the pond because being moved is stressful for them. I know you love your fish and want what's best for them - we all feel the same way - but your assumption that taking them indoors IS doing the best thing for them may not be entirely true. It's a stressful event for them all the way from being caught to acclimating to their new home. And then come spring, they have to do it all over again. And there are people who speculate that pond fish need a period of cold water. I don't have the science to back that one up, but it's definitely been postulated more than once, and it's an interesting theory.
Having said all that, there are people who do move their fish every year and do so successfully. I think the suggestions you are getting are just so you know you don't HAVE to move them.
Someone mentioned the weight of the tank - a gallon of water weighs over 8 pounds, so you are talking about 2500 pounds of just water, not including the tank itself plus any equipment. Unless it's a basement or garage floor, you may need to carefully consider whether the space you choose can support the weight of your set up.