Hello,
This is firm and office-dependent, but generally speaking project manager/engagement manager level and above are involved in interviewing candidates. However, analysts/associates/junior consultants are also often involved in the recruiting process through giving case workshops, running practice interviews with candidates, acting as a recruiting ambassador, and in some cases doing first round interviews. In my experience as a candidate, junior consultants can be great coaches too, and often charge lower prices, but of course it's totally up to you how much emphasis you want to place on seniority.
I would also recommend messaging coaches to do some due diligence and talk a bit about your needs and their approach before booking a meeting. You can message any coach you are interested in working with on PrepLounge.