First and foremost, welcome back! I'm returning to the game as well. :0) Second, what a BEAUTIFUL mare!
Fit is a funny thing. It's difficult to tell what fits best in photo form, but based on these pictures, I would say option one or three. Two looks like it would put a lot of pressure where it touches behind the wither. That said, you could find a saddle that appears to fit, and realize after a workout that it's pinching her (dry spots under the saddle). I would take her to the shop, or have someone come out to fit her and then give it a go. Good luck!