the shots are fine overall, except last one. And perhaps the third one. Model on these ones have very nasty shadows covering her face, and last one is actually lacking everything. The fourth one is in my opinion the best. 2nd place goes to 1st one in a row.
--
Second picture have very charming "straight and tight legs pose", but it need better framing.
Good job overall, and yes - I understand concern about using fill in flash.
It's hard to get the light to seems natural, and to not spoil atmosphere....
..
lightning need much practice... You could use just a reflector filler to bounce some light on her face, and you'll be good.
--
but as i said, not so bad job here
I'm glad you post it, and you're not afraid of critique. Every one of us need it, to become better photographer.
Thumbs up