THIS QUESTION IS SO HARD. with the disclaimer that my bird knowledge is most extensive for north american species...

mob is difficult. i feel like he should something small and kinda boring-looking, but then there's the question of his psychic powers... so perhaps he'd be a junco (common as dirt, small, cute in a vague way, does best in flocks) that occasionally becomes an osprey (big, fast, not exactly colorful but still striking and distinctive, predatory and intimidating-looking but not really a danger to other birds). or maybe everyone assume he's a sparrow because he's small and dull and unremarkable in a "yeah, that sure is a bird" way, but he's still in his juvenile plumage and will soon reveal himself as something entirely different...

my corvid bias says reigen would be a jay - loud, colorful, smart, sociable, sneaky, hilarious, obnoxious. has favorite foods, but isn't picky. if he and mob were in the same tree, your attention would almost certainly be on him unless you were specifically looking for unremarkable little dudes small enough to hide behind a clump of leaves.

i spent entirely too long thinking about this and still feel like i could come back to it in an hour and have a completely different answer haha