We would like to know if our Product Director is required to sign off for final approval on PDs, CDs and FRDs under DoD Acquisition or can our System/Operations Chief sign those documents and brief out PD?
Local and component administrative procedures should dictate staffing for technical reports. However, IAW the Defense Acquisition Guidebook (DAG), chapter 4, the program manager approves technical reviews as specified in the System Engineering Plan (SEP) developed by the Systems Engineer. More intensive coordination and staffing will largely be determined based on the ACAT level and who is the MDA. The higher the ACAT and/or MDA, the more involved the review of acquisition documents going up the chain is likely to be.
For templates, reference The Office of the Deputy Assistant Secretary of Defense (ODASD) Systems Engineering at http://www.acq.osd.mil/se/pg/guidance.html
. In the particular scenario you described, I would be inclined to have the System/Operations Chief prepare the technical report as the submitter with the program director as the approver. That way you are not overriding anyone's authority. But, again local procedures should be followed.