I am engaged
CORRECT
My family and I are friendly
CORRECT
You is good students
INCORRECT - You ARE* good students
They not are beautiful
INCORRECT - They aren't beautiful
I am are happy today!!
INCORRECT - I AM happy today!!
Ana and I am best friends
INCORRECT - Ana and I ARE* best friends
We is not strict
INCORRECT - We are not strict
You are at home?
INCORRECT - ARE YOU* at home?
You are not Mexican
CORRECT
I amn't a chef.
INCORRECT - I AM NOT* a chef
Are we alone?
CORRECT