Also you don't seem to have a clear picture of what Carfax is supposed to do. It's not going to report that status of any liens against it. An single accident 10 years ago on a car that's 20 years old isn't really that concerning IMO. You can easily get it checked for frame damage. It was a "reported" accident, which could have been as simple as a fender bender or something else minor.
If there is a lien against it, that means someone owes money on it. That means that person has the right to repossess the car if the payments aren't current. I'd run, this sounds sketchy.