Final answer:
To ensure SCADA system interoperability, the Network Engineer and Facilities Manager are the key stakeholders in the configuration process because of their respective roles in network infrastructure and facility oversight.
Step-by-step explanation:
To ensure interoperability between the legacy system and the new application in updating a company's SCADA authentication system, the stakeholders that should be involved in the configuration process before deployment are likely the Network Engineer and the Facilities Manager. The Network Engineer is critical for ensuring that the new application will integrate seamlessly from a technical connectivity perspective with the existing network infrastructure. The Facilities Manager would likely be involved in the physical aspects and may have oversight over the SCADA systems within their facility, ensuring the application functions correctly in its intended environment.
Furthermore, the Facilities Manager may have valuable insights into how the system is used on a daily basis and could provide necessary context for how the authentication should work. The Network Engineer and Facilities Manager both have important roles in addressing the human factors involved in the system's design and in complying with any industry regulations, such as those from the Nuclear Regulatory Commission or the American National Standards Institute related to ergonomic design and work safety.