Oh, and as for the "lips" of a gryphon's beak, I used this visual as inspiration.
https://thumbs.gfycat.com/TerribleHauntingChanticleer-mobile.mp4
As for the tribal facial painting and feather plumage, I only got this for the former.
https://youtu.be/JwLMY2q5_Wg
With what I planned for Roseluck, I was thinking of subtle facial outlines that would indicate something akin to her cutie mark. With Methos, I was thinking of deeper eye shadow paints to indicate a "mask" for him, something in like pic related. Save for it being more detailed and expressive.
2nd pic would be something akin to the size of Methos, and general body shape, with the beak trimmed to be less jagged of course.
(Scratch that, those pics are too big for this site. Darn.)
Good lord, I like better visuals, but I am stuck with what I got since I am not an artist. Just a penwriter. Nonetheless, I hope these will be a boon for you as far as a brief spot of entertainment goes.