Thank you so much everyone! I hope I can contribute some to the group, although sometimes I think I have more questions than answers, LOL.
As far as ducks in mixed collections go, Crtrlovr, there are probably several that would work for you. Sometimes, I think temperament with other birds/animals is more about the individual animal than the breed (not always of course). We keep all of ours separated in small groups by breed though once they are adults, so I am not sure how they would be long term with other types of birds.
In general though, the Mini Appleyards are my favorites. They tend to have the best, calmest and most easy going personality of any ducks I have ever kept.