No one is called homophobic slurs but there is still LOTS of homophobia in the movie. The characters generally act like being LGBT is a bad thing, including the main character. There is a comment from Veronica's mom suggesting that she's "playing for the other team now". Veronica says no and her mom says "Thank God, because your father would die". Sierra says she's not a lesbian and Veronica says "She just has no taste" implying lesbians can't have taste or be stylish/fashionable. On the phone Jamey compliments Sierra's deep voice and she teases him about the possibility of being attracted to men ("Oh because, what, you're super into dudes?") The joke relies on the idea that Jamey being gay or bi is something worth making fun of. In one scene Veronica tells Sierra "I'm not going to lez out with you and Jamey, if that's what you're asking" and Sierra responds with"Eww!" before saying no. Veronica then says "I only do that at parties" (acting intimately with with other women at parties is something that straight women often do for the attention of men and undermines the validity of LGBT women's sexuality). Sierra complains "Why does everybody think I'm a lesbian?!" Finally there is one joke related to AIDS which came off as unsavory in general but can be considered homophobic given that gay and bisexual men are the population most affected by HIV in the US. Dan says "AIDS now is airborne, so we're all gonna die". Not only is this insensitive but inaccurate as well. And this isn't even counting the parts with transphobia and interphobia.
Yes, an annoying amount. There are two instances where faking a condition is portrayed in a humorous light. The main one is Sierra pretending to be deaf. She seems to ad-lib some hand movements without true knowledge of American Sign Language, which comes off as mocking (signing her name as "Shit Pizza"). In another scene, Sierra and Dan joke about putting that they have schizophrenia on their college resumes so that they stick out. Ableist terms are sometimes used ("psycho stalker"). One joke where Veronica accuses Sierra of taking "crazy pills" (med-shaming isn't cool).
Not shown on screen but Veronica mentions her dad leaving her mom for a 22-year-old. Spence's age is never mentioned but he is in college meaning he's probably older than Veronica (might make some viewers uncomfortable).
Not slurs BUT it's worth pointing out that there are some transphobic moments in the movie. Veronica accuses Sierra of being trans in class as a way to attack her. She also makes a joke about her being on "hormone pills" (most likely referring to pills for hormone replacement therapy in transgender patients based off her previous trans joke). Later, on the phone, Sierra and Jamey joke about her "mannish" voice, and imply that Jamey liking a girl with a deep sounding voice makes him "super into dudes". Also this is interphobia and not transphobia, but still worth noting - there's a joke where Dan calls Sierra a "hermaphrodite" (outdated/misleading term for intersex individuals) and then quickly reassures Jamey "she's all lady parts".
In addition to the other comment where it happens, there is also a scene (at the party) that makes it seem like Sierra is going to do it after chugging alcohol BUT she doesn't (she just burps after a long pause). Just letting people know since the scene is done in a way to make it seem like she might, but it's a false alarm and the only actual v* scene is the one on the field.