Double check your zoning and ordinances immediately. There may be limits on how many and what kind. It takes just one disgruntled neighbor to get called upon too. (here you may have four hens, or up to four fowl, hens and ducks mixed, nothing else. Also no roosters in town, and a distance to other houses rule that mostly excludes everyone from having them. I do have
enough land I have a spot I can keep them....)
From neighborhood
experience things can smell and get noisy fairly quickly and not endear you to those that live around you. Neighbors that say no-problem may change their minds a few months later. Free eggs only go so far.
Be very careful of your numbers, hens can lay eggs without roosters (who if they are doing their job will usually make noise all day long), and the handling of manure/bedding to keep smell down will be important. Muscovy ducks are a little less water needful than other varieties, but. They can be great natural bug abatement.
What seems fine now, may indeed get to smelling 2-4 months down the road, and it may be that the wind blows it away from you to someone else. Here a lot of people use swamp coolers and sucking that into an evaporative cooler and spitting it into the house doesn't make for goodwill.
This neighborhood has had a lot of urban fowl issues over the past decade or so. In order of noise issues (descending): Gander, goose, rooster, ducks,
chickens. If you take 1-2
chickens as One, ducks are about a Three if you have two and don't encourage them to quack. Four to Five if you have mixed sex and are encouraging to quack (had a neighbor that thought that his four making noise all day long was great, it wasn't). Rooster, Four to Six. His voice will carry too. Goose, if she gets riled up, about Five to Six. Gander, Eight easily. And they never shut up (experience here on one that ran the neighborhood for a month, long story). Guinea Fowl, when riled up, Ten. They are keen bug-scarfers. I wanted some for tick control but they can be SO noisy.
Two drakes may compete, two females will probably be a lot quieter, and they will lay eggs for you too. Ducks are serious slug destroyers, I agree there. Last place I lived the slugs were terrible, but zoned for no urban fowl. I actually asked around for a rural person that had a few ducks if they'd be willing to loan me one for a day (for rent $$$) to help clean up my issues. Didn't find one, sigh. Above all, good luck in your attempt. I have not kept ducks in town but that is the experience I've had from living with neighbors who have tried to keep them....