I am not aware of Harvey Mudd giving admissions preference for recruited athletes. I am not saying that it does not. Just that I have not heard. Did you get, or can you ask for, a likely letter from the coach? Have you had a thorough pre-read at Harvey Mudd? I know at MIT athletics can give a person a very slight boost if they already have amazing stats, but nowhere near the boost one can get as a recruited athlete at the Ivies or NESCACs (and MIT does not give out likely letters). Is Mudd similar to MIT in this regard? I suspect that both the schools you are considering fall into the “slight reach” or “reach” category for you. Wrap this up and start looking for match school for yourself for the RD round. If money is an issue, be sure to look for affordable schools or schools where you might qualify for merit awards. Deadlines for honors colleges within some state schools are imminent. Don’t miss your next big opportunity because you are too focused on ED. You can be happy at any school if you find the correct “fit” and it most definitely need not be the most “elite” school you can gain admittance to.
Ending thought: Don’t change your ED application from C to HM unless the admissions there has given you super strong indication of admissions hopefully in the form of a likely letter. If you are only hearing positive vibes from the coach, then ask very carefully what admissions has reviewed and exactly what they said. Best if you speak to admissions.