“Final stages would include DT (Developmental Test) and OT (Operational Test).”
I am willing to waive those requirements in wartime, under the “hurry up and kill those bastards before they kill us” exemption.
There are certainly ways to expedite the process. For example:
Low Rate Initial Production (LRIP) decision could be made after the first successful test flight.
DT and OT could be combined.
Etc.