Esta is the singular version of estan when you are only talking about one person, either a man or a woman. Estoy is the spanish translation of I am sleeping. Estamos is when you are talking about a group of people that includes yourself. Therefore, estan is correct because you are talking about a group of people sleeping that does not include you.
3. What do you ask for when you go to a Chinese restaurant?- 4. Do you ask for water or soda? -5. Who brings you the food in the restaurant? —— hope this helps :)