So I’m planning on asking one of my teachers to do a recommendation for me. He is an alumni of the school I’m applying to, PLUS he’s my AP Cal teacher and former Pre-Cal honors teacher. We have a good relationship, though I would say I have a better one with two of my other teachers.
So, would I benefit at all from having a recommender who attended the school?
No not really, He’ll write a generic rec letter which you’ll use for all your applications. He doesn’t get a chance to declare “I’m an alum of X and I think IsaacTF will be a great fit”.
Not really, the school is evaluating you not your recommender.
Your recommenders should be people who you like, and who also like you. The rec is all about getting insight into your character from impartial people who know you well. Go with the teachers who you get along with the best, ideally in two different disciplines, and where you have worked hard and shown effort. You want a rec from someone wo will best emphasize your good qualities.
Ideally, you want your LORs to look like this: http://mitadmissions.org/apply/prepare/writingrecs
Like @happy1 says, it’s not about the writer, it’s about you. An enthusiastic first year teacher will write x500 better than a bored alum of your dream school.