Schematically they have the same base defense, though Bronco/Poppinga's style is more aggressive. But Kelly's knowledge of the program would be a huge attribute in this scenario. If Anderson were to get the job I'd be more comfortable with Peterson, who has actually run his own system as opposed to Beck who would be on his own for the first time.
The only name that really checks all the boxes in your scenario is Nick Howell, depending on whether you believe he is a legitimate DC at UVA. If you believe him to be a real DC right now, then he has coordinator experience, he has extensive knowledge of BYU's "uniqueness", and he runs a system that we all know can succeed here. The only question is who would he bring in as OC (likely Peterson). People scoff at Howell, but being a head coach is more about organizational leadership than personality, and I think he has learned a lot from Bronco in this respect. The fact that fans can't get over his failures as a young DC in 2014 says more about their lack of understanding that coaches grow and progress than Howell's ability to run a successful program.