I read the letter. There isn’t even an official signature from the attorney on it, statements are legal documents, they should be signed.
So your theory is forgery? Unknown forger or do we have a suspect? Not perhaps that this letter isn’t actually a statement or a legal document, but a mere offer, and doesn’t require one?
Either way, forging documents from a well-backed law firm and then publishing them on your website seems like a recipe for getting sued out of existence. Why do you think the law firm is showing so much restraint? You think maybe they’re getting leaned on?