Since you mentioned increasing aggression, I need to say, don't back down from any confrontation she or you start. If you do, she will learn more and more tactics to push you away. It would be hard to adopt out an iguana who greets visitors with a wide-mouth hiss or a lightning-fast well-aimed nip.
I know you are already planning it this way, but make sure you don't give it to a noob. The adopter must have good basic knowledge of tropical lizard care and have money to spend on a proper habitat and exotics vet care.
I can just feel that an adopter will show up any day now. Use this as your and the new owner's Bible of iguana care:
It has everything you need to know.