Step-by-step explanation:
The first one is "ella," as you are talking about a girl, and "ella" means "she."
The second is "ellos," which means "they."
Next is "ustedes." What makes it different than "ellos" is the fact that you are talking directly to them!
Then, I believe it would be "ellos" again.
Next would be "el," since that's the word for "he."
Talking to the mother is "usted," because it's a more formal version of "you."
And lastly, "tu." Because she's a classmate that you already know, you use the familiar version of "you."
I hope this helped!