I went for what I think would look best on a banknote, so animals with some ‘presence’ - hare & fox, kingfisher & curlew, salmon & dragonfly.
Bank notes in the Netherlands used to feature snipe. Odd as it may sound, those birds looked like they were designed for that purpose. Curlew have a not too dissimilar vibe.
I do question the rationale of suggesting a bird that it’s on its way to becoming functionally extinct, but I’m sure the panel considered that.