One year I opted out of Eisenhower and just did Pierce. I got back early enough to go add Willard to winter. (For my personal list) I'd say if you went up C-Path and down Edmands, and you had gotten to the parking lot you would have made it. Not sure on a backpacking trip. If I do Madison and Adams and spend the night at an RMC Cabin, then do Jefferson after the equinox, do the first two count for winter?
Many moons ago now I did the Kinsmans on the last day of winter, stayed at the shelter, and then went up and out over Cannon the next day. The Kinsmen were my last winter 48s. So I duly sent in my paperwork and applied for the patch, and was informed that, no, I hadn't come off the mountain in winter. Needless to say, the next year I did them dead smack in the middle of winter. It was an AMC hike, and my co-leader, unbeknownst to me, made homemade ice cream for each person, put them in individual zip lock bags, secretly carried them up in the trunk of his car and then his backpack, and we ate them at Lonesome Lake Hut. It was a touching way to finish.