son or estan
I think it is "son" as it is an essential characteristic of the two. While not permanent I still think "son".
The word you want to use is "son" because their profession is considered to be students.
Hope this helped!
It is son, look here ser estar to learn more.
Ser - intrinsic state of being. It isn't something that is going to go away easily.
Estar - State of being temporary and state of location, to be located/situated at a place or in a situation.
Would the second explanation be OK and understandable?
Ser, which means "to be", is used to express the identity of the subject.
Yo soy médico. I am a doctor.
¿Ustedes son ingleses? Are you English?
Elena and Ernesto son estudiantes.
Here is an example using estar:
Elena y Ernesto están estudiando. Elena and Ernesto are studying.