She is an adult, she signed the contract, photos are yours to use in your portfolio and there is alot of chance that this will stand in court on your favor.
The only thing i am wondering about the pictures is: Are they that good that you are ready to put time and effort in all that, go in court to put them up on your portfolio? Are the models know each other? ditch the pictures IMO and re-shoot with the other two models if they really want the pictures.
I dont wanna be rude but if you just started working on your portfolio, i dont think the quality of the shots you took (We all went trough this when we first started.) are worth the pain and trouble to go to court . Get on model mayhem, Schedule with TF models and shoot again.
To have a SOLID portfolio, you will need more than 1 shoot to get it completed.
Maybe more like 10 to 20 GOOD shots.
Just save you time, drama and pain , tell her to grow up. and re-shoot with models that knows what the hell they want.
P.s add a line to your contract that stipulate that you will NEVER delete your work on any models request. lol