Ben - in this scenario using CSVDE would be a good approach. since AD & DNS are in an error state you will have to fix them if you plan to use either ADMT as well as SBS migration with an answer file.
also it could save a lot of time depending upon how badly the AD is in.
you might also want to use robocopy for copying the users directories from the server, as well as USMT for profiles depending upon the w/s