Clipping feathers is not a terrible thing to do, if you do it right. It's just like giving them a hair cut. We try to minimize the clipping, just because we like to watch them fly, and it allows them a bit more chance to escape a predator. (We keep them in an enclosure at night, and only let them wander during the day while we're home. Still, that hasn't stopped hawks from taking a dive at them, even when we are standing only 4ft away.).
For our two mallard drakes, we find that clipping the alpha is sufficient to keep both in the yard. We start off clipping three flight feathers on one wing, and that's usually enough to keep the alpha from going more than half a dozen feet at a time. Once we had to go for a fourth feather. The beta then still has full flight, but he never leaves the alpha behind. (And he's quite the precision little flier, even managing to fly up to me an land on my shoulders.)
As for winter housing, make sure it stays dry, has plenty of ventilation but no drafts, give them plenty of fresh straw on the inside (you will need to turn over the straw every couple of days, and change it once a week - they are poopy little creatures) and they should do quite well. Once it goes below single digits F, we'll bring them in for the night. (But I've certainly heard of people leaving them out in colder weather - ours will sleep outside, even though they always have their coop with straw, for anything above ~30 F.) Heated buckets to keep their water unfrozen, and plenty of food to keep their metabolisms up and keep them warm.
Occasionally during the winter, we'll bring them in and let them swim in the bathtub. Otherwise on the few nice warm, sunny winter days, we fill a tub for them and let them go swimming. But they definitely get less water time in the winter months.
