Many thanks to everyone for sharing advice! It's a lot of help to be able to bounce some ideas around. The plan I've worked up will have a traditional coop-and-run along the back fence as the hub, with three paddocks as radiating outward, divided by a wire-and-shrub hedge. By using ducks, it will be easy to get fences down to around 2 1/2 feet, which should be more aesthetically pleasing than a higher wire fence and let me simply step over them when I want to. I worked up a plan that can put some of these hedges on or near contour so I can pair them with a series of small swales. Those can be deeply mulched to absorb spilled water (and hopefully smell). I've put together a plants order I'm giving the final thoughts to that will consist of dogwood, aronia and buckbrush (also called coralberry) for the hedges, and I already have an order pending that includes some redbud trees, golden currants and serviceberries. I can get goji seeds to help fill in some spots with a good nitrogen fixer.
I looked through some videos of different breeds of ducks, especially where a couple breeds were present, and these seem to confirm the hatcheries' general consensus that the Welsh Harlequin are relatively quiet (probably quietest other than Muskovies). That makes them my top choice, at least for now... I'll probably go back and forth a few times.
All that said, it seems that there isn't much difference in planning for chickens or ducks at this stage of development. If I decide to go with chickens I'll just have to go with a fairly heavy, docile breed (Buff Orpingtons... maybe Barred Rocks) that aren't as interested in escaping, stretch some wire on poles above the hedges, and maybe clip a few wings if that doesn't work. It doesn't seem like it would require the 6' tall fencing I led myself to believe. Beyond that, I would have to modify the coop design, and I could move my compost pile into their run and let them work it over (instead of doing it all myself), then maybe fence off some more fragile plants within the paddocks. ...That's pretty much it.