While there are some standard humans, *most* of the people we see (aside from the primary cast) are humanoids with some vaguely canine features (the nose, mostly), rather than actual humans:

There's Chief O'Hara (no relation) in the Mickey Mouse stories:

[![Mickey's friend, Chief O'Hara][1]][1]

There's the Beagle Boys, of course (their dog-like noses are a bit more prominent than usual, probably tied to their name):

[![The Beagle Boys (and Scrooge)][2]][2]

And, in the Barks and Rosa comics in particular, these same creatures tend to populate crowd scenes:

[![Donald and Scrooge "falling" through bus][3]][3]
[![Donald and Scrooge on celing, over crowd][4]][4]

(These last two images from the Don Rosa story "A Matter of Gravity").


  [1]: https://i.sstatic.net/uA8ZM.jpg
  [2]: https://i.sstatic.net/FtEz3.jpg
  [3]: https://i.sstatic.net/1sz3N.png
  [4]: https://i.sstatic.net/IAy4A.png