What is the one definitive publication, standard, directive, etc.... that provides the formal and approved template for what constitutues an acquisition strategy at all the various phases of the acquisition process?
Yes, there is a standard format for an Acquisition Strategy, and also for a Technology Development Strategy, which was issued by the Office of the Principal Deputy Under Secretary of Defense (AT&L) in April 2011. A policy memo dated April 20, 2011 announced the "Technology Development Strategy or Acquisition Strategy” template. This memo and associated template expanded on an earlier August 20, 2010 memo that provided direction on the level of detail required for certain acquisition strategy topics such as “business strategy.” The substance of August 2010 memo was incorporated into the April 2011 template. All three documents can be found at https://acc.dau.mil/CommunityBrowser.aspx?id=534311
Please note: Templates can be misused if taken too literally. Not every paragraph in the Acquisition Strategy template will apply to every program – judgment is required as to what is appropriate. The Acquisition Strategy template is definitely NOT intended to be used as a checklist, but rather a guide to achieving a comprehensive picture of a program’s Acquisition Strategy. Paragraph 4 of the template specifically recognizes tailoring of the Acquisition Strategy as legitimate in accordance with the principles and policy of DoDD 5000.01.