Depending upon the year of baptism and marriage, ie. pre-V2, it should be assumed valid, no? If afterwards and no video, photos, or living witnesses are available, what about re-doing it conditionally? That should cover Sacraments such as Baptism, Confirmation, Confession (make a General Confession), but marriage? I just don’t know unless there are no complications for either party, (annulments, etc.). Then can’t it be re-done conditionally as well?