(1) Hopefully, a teacher will soon answer you.
(2) I found this in one of my grammar books that MAY (possibility)
(a) We ate a HOT dog. = we ate that popular American sandwich.
(b) We chased a hot DOG. = the dog was hot.
If we said: We ate a hot DOG, that would not be considered a nice
thing to do here in the United States.
And if we said: We chased a HOT dog, that would mean we were
chasing that sandwich!!!
(3) So I think (only my opinion) that you are correct:
Tom: Hey, buddy, don't go to the dance with Martha.
George: Why not?
Tom: Because she is my GIRLfriend! That's why not! Keep away!!!
Sue: Are you going to marry Mona?
Ralph: No way!!! She is just a girl FRIEND. Nothing more!
***** Thank you for the question *****
P. S. I think that most people would simply say:
She is just a female FRIEND.
Student or Learner