1. There are policies to help place-specific senior candidate groups such as war veterans, scientists, diversity hires, etc. However, there are no programs that I am aware of that are purely age-based
2. Lateral hiring for senior candidates happens for very specific roles such as Principal/Partner levels with a focus on practice areas OR as subject matter experts, sometimes on a contractual basis for a case. It will be very difficult to join as a generalist consultant since most general consultant recruiting at junior levels happens at universities. However, you could aim for a more senior sector focused role based on your background
3. Based on the role that you are applying for, your preparation should be a mix of case interview preparation as well as for fit based interviews (even more important for senior roles).
4. I recommend applying to senior roles. If you don't have previous consulting experience, as apply as a subject matter expert to support case teams in topic of your expertise. If you have previous consulting experience, apply for a senior consulting role such as at Principal/Partner levels
Best of luck!