I'm kinda a "black sheep" around here - unconventional duck keeper. One set of my drakes (large Swedish breed) live on my pond at my farm. They have a brushy cove in one corner of the pond, they can swim under, with 2 entrance/exits - one in the water, one on land. They don't have a "house" and they don't get locked up at night. I do not clip wings. We do have some predators around, and yes, I have lost a few (not many) ducks over the past 3 years, but I feed them, and we keep the area around the pond weeds cut back, and they seem quite happy, and they know it is home, so they stay.
I also have call ducks at my house. They have a huge fenced/net-covered run, but they also do not get locked up at night. The girls use their house for laying, and maybe someday, for brooding!
Call ducks can fly very well. Have you seen these 2 ducks flying? Be careful how forceful you are with them. Let them come to you, or you may permanently run them off. Giving them a "safe retreat" place will be nice for them, but unless they were handled a lot as youngsters, they will be very hard for you to fully tame. Just getting them to come to you for treats will be hard enough. Touching them may never happen. My pond ducks know me and come running to me, but will no longer eat out of my hand. 2-3 feet is about their limit.
Best of luck!