Katie would be a kestrel. You've got the obvious flying/Quidditch connection, but I particularly like kestrels because they're birds of prey (Katie's not a delicate/flighty person) but they're also relatively small and don't look threatening.
Ingvardine would be an arctic fox. I did consider a polar bear, but she's shaking her head and saying they're too big and rounded. Foxes are quick and sharp and sly.