OK, I finally finished! I decided to draw Cornelius and Rin as they'd appear in the Finding Daecon's Way world while trying to keep them still looking like your characters.
Cornelius's mammal alternate is a red giraffe, his bird alternate is a red flamingo.
Rin's mammal alternate is a grey squirrel, his bird alternate is a blue hummingbird.
Note that in the FDW universe the animal alternates of the shapeshifters often don't have the same colours as their wild counterparts. This is why I chose to make Cornelius a red giraffe and a red flamingo instead of a brown/orange giraffe and pink flamingo - I wanted his colours to look like they do in human form. As for Rin: Well, a blue squirrel could exist in my universe but I think he looks better grey.
Now, you've already drawn Daecon from Finding Daecon's Way... How about one of Carmen from Wild Nights, Hot and Crazy Days? You could do teen Carmen:
...or grown-up Carmen: