As you are aware, the payments that you received under a mortgage assistance program were not a reportable or taxable event.
Property taxes, mortgage interest, escrow fees, etc. are normally reported on the Form 1098. If you do not have a Form 1098, the Form 1098-MA you may have received includes the same information.
However, home deductions are only deductible in the year that they are paid and not incurred. Therefore, if the loan was full paid by you after 2015 (you indicated that it included property tax and the mortgage interest) then you cannot file a 2015 Form 1040X to claim the deductions.
