There was definitely something moving under the boy's robe. Theodore definitely saw it. It wasn't some figment of his oft-unreliable mind and he knew it. He would just...keep an eye on it, for now. Timothy seemed like the kind of boy who would introduce a pet to a new friend, so what...?
Theodore considered that question, putting aside the comment that Snape was scary. Yes, he could be. "Ah, well...I think I am passable, but...NEWT-level Potions is rather...demanding, and, uh, exclusive. I had an O on my OWL so...yes?" It was hard to give himself credit in most things. "What...classes do you like, Timothy? Care of Magical Creatures? You seem...the animal-lover type." So maybe he wouldn't just watch.