You need a good pinch of handwavium to accomodate the character playability, but it obvioulsy won't lead to broken things (which is not inherently bad if you are ready to handle it), more important, it won't result in one mage being clearly favored compare to the other. So disregarding rules & co, it is a nice concept for a PC magus.
Talking about handwavium...
As it was already mentionned, the fact that he is not Gentle gifted is the first, big, main hurdle. From a purely mechanistic view, it is possible to design spell that can grant a +3 bonus to social, thus nullifying the malus imparted by the gift. It does cancel the malus, it does not remove the unsettling effect the Gift give. People will still be uneasy in the presence of the character, won't trust him and might even secretly hate him. They might also find strange that when they are in his presence (and because of the spells he is using), they are "kind of fine" talking to him, but as soon as they leave him, they cannot help themselves but think "why did I talk to this guy ? my guts tell me I can trust him, yet I still talk to him".
Also keep in mind that casting frequently spell on people impart Twilight (either for high magnitude or long duration). You can argue that if he is teaching only 2 seasons a year, it is not long enough to count as yearly duration. YMMV, people will be under his spells a good chunk of the time.
But because of that, he might not be able to be paid what he is worth - despite being a good teacher, his gift prevent him from being acknowledge by his peers as the master he is, so he should have to fight for his reputation and salary. That's already nice story plot for him. Because of his Gift, smear campaign and disputatio against him will work well as people would initially distrust him. Strangely enough, people who never met him and only read his work will acknowledge him for his true skills... until they meet him and then they will possibly start give credit to all these unpleasant rumours (stealing somebody else work, having dubious habits, etc.).
On the other hand, he should be receiving support from House Jerbiton, even if he is not member of the House. Just because he is a talented scholar. Maybe he even owns them a few favors (if he needs to balance his virtues with some flaws) or a Jerbiton is his mentor.
Another way he can bring money to the Covenant is by giving class to several magi at a time: he is a skilled teacher, competent in some interesting skills. If he can gather up to six mages or Redcaps who needs classes in Arabic or needs to polish their Latin to be able to write their first Summae, he can ask to be paid in silver. It is usually frown upon to deal in silver between mage as the true currency is vis or knowledge (books, tractatus), but in times of dire needs, who cares. If a season of teaching allows to have a well equipped lab, mage can swallow their pride.
Finally, when he will have some solid Arts, his tracatus and Summae will be of the highest quality and fetch a good prize.