Hope you NDSU guys don't mind an Augie fan jumping in here, but I have a little bit I can share about both of these guys.
As far as Jayden Olson goes, he'd be a great hire for Richman. When Jayden was at Augie, he and Coach Billeter brought in some of Augie's best recruits in school history, including Augie's top 2 all-time leading scorers, Cameron McCaffrey (#1) and Cody Schilling (#2). He's a sharp guy, solid personality, top notch recruiter, and is going to be a successful coach in the very near future. Frankly, I'm surprised he's stayed an Ops guy for this many years.
As far as Margenthaler goes, I'm willing to say I'd be shocked to see him take an assistant job at NDSU. This is not a knock on the Bison, but I believe Margenthaler makes $115,000 a year at a well-respected school with incredible facilities for the D2 level (frankly, for D1 level too compared to several low- and mid-major D1s), a ton of academic majors for recruits to choose from, a nicely-sized city of 40,000 people, and a gold mine of high-level D2 talent and low-D1 transfers from the Cities looking to get back closer to home. He's won something like 8 of the last 9 regular season conference championships at Mankato (counting both the final years of the NCC and the years since transitioning to the NSIC), and he has a ton of support from the administration, even if the fans don't show up to games like they probably should. I think it would take something like a D1 head coaching job to get him to leave the comforts of Mankato. Then again, I don't know everything. Maybe the opportunity at NDSU appeals to him. Like I said, it would just shock me to see him take an assistant job at this point in his career (unless it was an assistant job that paid substantially more than his current salary).
Congrats on Richman. Sounds like he's going to be great for you guys. Nice to have a system/program/community where solid coaches can simply move up the ladder and carry on the success of a previous coach.
P.S. - For the record, I'd love to be proven wrong on Margenthaler. Getting him out of the NSIC would definitely be helpful for the NSIC fans whose teams aren't Mankato.