I'll likely sort this and post the class listing in the NPCs section, under the teacher that helps do it. 

Alchemy - Lidda Sonnet; usually mixes restorative salves along with her Vitamancy magic to ensure better healing that doesn't always require magic. She also helps out Lucilia with her projects from time-to-time. 

Gardening - Ghell; the college's landscaper. While the overall maintenance of the college's many gardens and farms is done by various hired hands, he's often seen leading larger groups in big projects or simply doing work that requires his skills. He tends to show up just about everywhere in the college, often as soon as someone does something to damage his flower beds or general vandalism.

Forestry - Overseen by Lucilia

Underhaven - While Underhaven is known to the College, the one who "runs" it (That is, cares for the day-to-day operations) is an old friend of Lucilia, one of her former students. Not a mage herself, but cunning and more than able to take care of things in Underhaven. 

Metal Working - The Forge is technically under the college's control, but Tyrael makes the most use of it and often has his demons in there constantly shelling out arms and armor to sell or working on one of his projects. That being said, the one who leads them when Tyrael isn't there is one of his former Familiars, who he released sometime after he earned his mastery over Demonmancy. The Familiar is very loyal to Tyrael, if ambitions. 

Arts and crafts - Val

Monster Hunting - Overseen by Tyrael

Warding Classes - Still a former student of Satori; while a master class in terms of ability, has yet to learn the Domination spell as he is still "Unworthy".

Creative Writing - Justine Flowerstyr; he can write as many books as he can speak, which is a lot. While not much of his work has been published, he encourages others to speak thoughts onto paper.

Investigation Squad - Overseen by Satori