ASK A QUESTION son or estan
elena y ernesto (estan or son) estudiantes
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!
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.