Anyone including non-designers can use this framework to analyse a product or service or analyse a piece of work for a potential client. You could even use this to review your own work as the tools and techniques I use leave little room for bias.
Agile is an iterative approach to project management and software development that helps teams deliver value to their customers faster and with fewer headaches. Instead of betting everything on a "big bang" launch, an agile team delivers work in small, but consumable, increments. Requirements, plans, and results are evaluated continuously so teams have a natural mechanism for responding to change quickly.
Domain Experts / Subject Matter Experts / Industry Experts have invaluable knowledge that you can (and should) apply during your UX process. Domain expert involvement is not an alternative to UX research, and a domain expert is certainly neither a “user expert” nor a designer.
Interviews
Domain Expert Interview — UX Knowledge Base Sketches