Hi obiter dictum,
EssaySnark feels you have a lot to work with and this profile should be appealing to the top programs (when positioned correctly and with a shiny GMAT score of course!).
EssaySnark guesses you're applying to HBS and/or possibly Stanford.
Rule of thumb: Choose recommenders you've worked closely with for at least six months, within the last three years, who were in a position of authority over you and can assess your workproduct.
EssaySnark's first-choice combo of three for HBS:
- old direct line manager at PE firm - EssaySnark likes this since it's the most "traditional" of the recommenders and fits into the "direct supervisor" box the best.
- own business - no can't write own (EssaySnark knows you were kidding) however if you have any big clients (or possibly a partner, though not as good), then they would be ideal - anyone in this category? The successful exit of this business should be a cornerstone of the app (depending on career goals), and getting a LOR from someone involved with you on it in some way would be, in EssaySnark's opinion, a key addition to your pitch.
- charity - this supervisor sounds like a good pick DEPENDING ON YOUR CAREER GOALS (if not in a social venture/nonprofit thing then maybe not quite as strong) -- and, by the time you submit for R1 in October, then wouldn't it be five months of experience? So still a little lightweight in terms of overall duration but geting into the acceptable range, and it sounds like you have a big "impact" story which is so important for HBS. Plus it's the most current, which counts quite a bit.
EssaySnark advises against using the priest,. He wouldn't be able to comment on your workproduct, right? Discussing your "development" isn't nearly as compelling. And, knowing you since you were 13 could be perceived as "family bias" (i.e., someone close to the family would only ever say great things, like if your mom wrote your rec - the adcoms often discount these). EssaySnark is not convinced there's a cause/effect relationship between his recs of your friends and their admissions to those schools. EssaySnark is sure he's a great guy and would write nice things about you, but how much real insight and concrete examples can he offer to the adcom about your skills/abilities in a professional context?
EssaySnark is more inclined towards the internship supervisor over the headmaster if having to choose, but in either case, this type of recommender would need to be positioned as a "mentor" to focus on the ongoing relationship -- and what they can say is somewhat limited. It's tricky for someone to discuss your workproduct in jobs where they weren't working with you. All they can go on are your discussions with them about the jobs. It's more "hearsay" than first-hand reporting. Not as valuable. But, if presented in terms of how he/she mentored/coached you, worked with you on your career path, advised you on the business perhaps, then maybe can offer value. So this could be a viable third rec for HBS if one of those identified above didn't play out for you.
Good luck with it!