"Some students in the class are short."
Translation:Algunos estudiantes en la clase son bajos.
Corto is used for length, bajo for height.
Creo que este pantalón es demasiado corto... I think these pants are too short.
Era bajo para su edad... he was short for his age.
No. If you use "cortos" it sounds like if they were silly, so this would be a funny misunderstanding :)