I live in a very similar climate to you by the sounds of it. Some of my fruit trees don’t become fully dormant until Dec in my climate. Even then some late apples still have leaves in Dec which I strip to promote dormancy.
I always wait until January to dig up and transplant my in ground fruit trees This way I know my trees will be in the most dormant state. Even in January my early plum trees are beginning to have bud swell if January temps have been warm.
The best time IMO is after a bit of a cold snap in January that will put them into their deepest state of dormancy. Once the freezing temps let up and the weather has warmed again is the best time IMO. The key is to never dig them up during freezing weather, but right afterwards when you hit a warm/wet stretch of weather.
The ground in my area is rarely frozen long enough to prevent transplanting, but best to wait until a bit warmer temperatures early in the year to dig up in ground trees.
Potted trees I usually transplant in Nov, to allow them to have some root growth and establish themselves over the winter. That gives the best chance for survival and good growth in the spring IMO. I would only recommend fall transplanting for those in warmer zones that rarely see extended freezing weather during the fall/winter.