I'm not sure how Gemma feels about him personally, even after reading, but she is friends with Siobhan, so there's that, and she's only a year below Max so she'd at least know of him. Draco's also friendly? with Siobhan, and is a fellow Slytherin so would definitely know him, even if he was only a 2nd year when Max was Head Boy.
I don't think Tess, Astoria or Mary-Anne would really know him at all. :( but there's always random run ins or stuff.