Lots of different questions here ... Look at SDSU ... they took a high profile high-major D1 assistant over a D2 head coach who just won a NC.
Its really about connections, comfort level and cultural fit. The two candidates considered "finalists" for SDSU came from the Greg McDermott coaching tree. Most of the staff members at SDSU are from the Greg McDermott coaching tree.
Ultimately the answers to most of your questions depends on the perspective of the AD filling the job. NDSU has shown a proclivity for filling their jobs internally. Being the #2 guy on staff there has proven to be a very good job. Richman is probably going to get an opportunity like Phillips, Miles and McDermott before him. I would bet that Jayden Olson remains on staff simply because history has been good to guys in his spot!