It appears that your questions center on evaluation data requirements and sources and how they are used. 

You ask about the development of the Critical Technical Parameters (CTPs) once located in the Defense Acquisition Guidebook..  The Defense Acquisition Guidebook has been retired and replaced by a modern set of 12 guidebooks aligned with the new acquisition policies.  According to the November 2020, Systems Engineering Guidebook, an acquisition development program should ensure that each Critical Technical Parameter (CTP) has a corresponding technical performance measurement (TPM).  The TPMs should evaluate the performance of the system or subsystem elements in achieving critical technical attributes (e.g., weight) that contribute to meeting system requirements. There should be multiple TPMs to monitor forecasted performance of Key Performance Parameters and Key System Attributes. The TPMs are called Critical Technical Parameters (CTPs) by the test community. Since the TPMs/CTPs evaluate the performance of the system to meet system requirements, they are used in the Integrated Decision Support Key (IDSK).

The IDSK (Integrated Decision Support Key) is a new tool to ensure test and evaluation focuses on informing the program’s decision-making process throughout the acquisition life cycle.  It shows the correlation (or mapping) between decisions, capabilities to be evaluated, measures to be used to quantify the capabilities, and test and modeling and simulation events. It also highlights the program decisions and data requirements and sources [e.g., contractor test (CT), developmental tests (DT), live fire tests (LFT), operational tests (OT), and modeling and simulation ( M&S)] to support those decisions, and correlates data requirements with critical operational issues and technical requirements.  The IDSK links DT&E, OT&E, and LFT&E information to critical decisions.  The IDSK provides a framework for how test events can build on one another and support the data requirements for multiple stakeholders’ evaluations simultaneously, producing efficiencies across the T&E lifecycle and facilitating the integration of DT, CT, and OT. The IDSK should evolve and adapt through the system lifecycle and identify opportunities to incorporate operational realism. As directed by the new DoDI 5000.89 (November 2020), the IDSK is included in the T&E Strategy and the TEMP (Test and Evaluation Master Plan).

I found reference to the "Data Source Matrix" in the 2005 "Test and Evaluation Management Guide".  The Guide states that "The objective of the Army’s emphasis on evaluation is to ...  identify data sources (data source matrix)... . As evaluation and analysis planning matures, focus turns toward identifying data sources as a means for obtaining each data element. A "data source matrix" is a useful planning tool to show where data are expected to be obtained during the T&E of the system.  There are many sources of data that can contribute to the evaluation.  The Army requires a System Evaluation Plan (SEP) that describes the evaluation approach that addresses the technical and operational aspects needed  to address the system’s operational effectiveness,  suitability, and survivability.

So from the information above, the primary purpose of the "Data Source Matrix" in the Army's System Evaluation Plan (SEP) is different than the purpose of the Integrated Decision Support Key (IDSK).  While the "Data Source Matrix" identifies where the data, that can contribute to the evaluation, are expected to be obtained, the IDSK supports the program’s decision-making process by highlighting the program decisions, the data requirements, and data sources to support those decisions. Both the “Data Source Matrix” and the IDSK identify the source of data used to support the program decisions; but only the IDSK supports the data requirements and the decision-making process.

The IDSK is addressed in the Intermediate Test and Evaluation (TST 2040) course curriculum.