There are already some options to come at least close with Ron, and I intend to develop this further. And I would like to add something with Vincent at some point, so I hope to add a bit more romantic soon.
Since the headmaster controls the grades, it is pretty tight with his opinion of you. You can increase them with Ned for a bit, and I plan to have other means to increase them in the future, but for now, it depends pretty much on the headmaster's favor.