i think for starters you can decide between whether you want something more akin to the animal itself or to just have elements that are similar (i.e. a feathered cape, owl like mask, night/moon motif)
if you go for more creature like designs you could look into harpy or griffins
another cool concept would be to build the design around the night owls shilouette so that they'd resemble the animal but it's a person
i know for zelda they had kaepora gaebora as an actual owl but there's at least one character whose motif resembles them because they're linked
all in all tho it just kind of boils down to the vibe you like the most