I am thinking of a Light teal pegasus... female might work better, and maybe a pink mane (I am not very good at deciding what I want sorry.) If you can add that top hat I wear in my show that would work well too. And for a cutie mark, do you know the heart at the end of my title cards, the three/fourths one from Link to the Past, that'll work.
As for Facial Expression and poses, I'll be fine with anything happy.
Again sorry for being a bit vague.