Is it fine to take only 1 AP sophomore year?

I’m taking one AP currently (as a sophomore) and it’s totally fine! Especially if it’s your first AP class, i wouldn’t suggest jumping straight into multiple APs anyways. You also have your junior and senior year to take APs. While many people say taking multiple APs immediately is the way to go, a lot of the time it’s really just a gpa booster. (as many top colleges don’t even end up giving the credit for a lot of AP classes)

I think it is completely fine to only take 1. In fact, it is probably better to ease your way into APs because some can be very challenging. And if it isn't a class you are particularly interested it makes the classwork and studying even harder. I also know many people want to take more APs for the GPA boost, but it isn't worth it if you get a lower grade in the class or it takes a toll on your mental health (I'm not sure what your course load looks like, but just keep that in mind as well).

As for Spanish, I agree that it would be so difficult to take a gap year when learning a language. I have taken spanish consecutively for 3 years now, and I have struggled to remember topics covered from year to year. Especially since languages need to be used in order to retain the information, its probably not in your best interest to take a year off.