@catmother
So the pup you guess to be Desmond's is literally named "feels Desmondy" in my group and has been since it came out from under the blanket.

It fits his style, plus it reminds me quite a bit of Aidan who is in the stamp collection.
I have been looking at the clues too and thinking...not nearly as hard as you have...but I don't think avian is the whole answer because in the crossover between the dressups and the stamp collection, we do have geese, ravens, and falcons, but also snakes, horses, and cats. I haven't had the spoons to do much research, but I've had nagging thoughts about the symbolic and mythological associations of those animals and I wonder if they overlap anywhere. (Random fact that's probably completely off-base, btw: geese are associated with Geb/Seb, an egyptian god of healing, farming, and fertility.) I'm also kind of fixated on the ghost plushie and jar of Dream Sand.
All the ??? answers on sensory questions make me think the final outcome must lack the senses those questions relate to or at least experience them too differently for the question to be answered. As in snakes, having poor eyesight, wouldn't care to choose between the aurora and the milky way...and neither a snake nor a predatory bird would have a favorite fruit. Plus there's that ghost...
Aaanyway, that's my bunsen-burner-melted two cents for the evening.
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While I'm throwing stuff at the wall:
Concept's third hint: Is it the curly-looking symbol and/or "believe in magic" in their staff bio?
or was it found already and I missed it lol