Lington

I teared up during that apple pie scene

https://www.youtube.com/watch?v=eOipaGDSBTQ

Skinny Pete!!

He's been out of prison for pretty much the entire time Family Guy's been out, though

Do you have a link of the clip? I've seen every episode but can't recall that moment

That specific teacher had actually removed Cho from her class and reported him.

"About six weeks after the semester began, Giovanni wrote a letter to then-department head Lucinda Roy, who removed Cho from the class. Roy alerted the student affairs office, the dean's office, and the campus police, but each office responded that there was nothing they could do if Cho made no overt threats against himself or others. After Giovanni was informed of the massacre, she remarked that "[I] knew when it happened that that's probably who it was," and "would have been shocked if it wasn't."

Usually I would agree but in this case I do believe that the teacher suspected it was him.

There was also another teacher who created a secret code with the assistant teacher for when she helped him one-on-one because she felt unsafe with him.

(All info from Cho's wikipedia)