I don't know the actual impact on your scores when it sells. Since she is making late payments every month, the sale of the house will stop the late payments and that will help you. Worst case you may have to wait the additional year, but I bet with the documents you have you can overcome the late payments she has been making since you can prove it was her responsibility to pay (in writing) and you made your payments on time and can prove those payments. By the way, the lender may want to see cashed checks for your rental history unless you are renting from a management company where a VOR will be accepted.
