I don't understand why you would not consider in advance to have plan A B C on Delta flights at N/C if you have a few days flexibility? (other than taxes)
NW privs are = in July after the merger joins bennies...what am I missing here? Are your required to book a ticket or just a seat request? Not understanding any of your dates re Sept then Dec
If you can still buy conf'd seats after 6/23 shakes out why not do it then?