Unsure of which double concentration or minor to pursue?? (undergrad)

Counterpoint to the CS answer, which I am inclined to advise against lest you become the CS guy. It might differentiate you, but if you want to be flagged for CS projects, go do CS. Otherwise, they're just going to put the people who can code on coding related projects. If you don't want to code, then stay away from CS, because doing it will only make them more likely to seek you out.

You get a quant major to show them you're capable of quant work. That's finance or econ. Then, for the second one, it doesn't really matter.

You have a few options, however: 1) Specialty degree. If you want to consult for healthcare, do biology or whatever else is prehealthcare. If you want to consult for TMT, do some sort of TMT major. Then either 1) apply to boutiques, or 2) apply to major firms and network into their XXX practice before starting. Inb4 you can't do that, yes you can.

2) Do something you enjoy. I recommend this most. I actually think it behooves you more as an applicant to have something on your resume that you can get genuinely excited about, so that when they ask you about your studies in an interview, your face can (with sincerity) light up and tell them about the most interesting thing you learned recently. That shit is infectious and way better than seeing another applicant who doubled down on business because he wants to be a consulting drone like everyone else. We deal with enough boring people day to day...

3) Do something strategic that you think you can spin to help complement your quant major. Your story will be, "I did Finance/Econ to hone my quant skills, and then I did Philosophy so that I know how to structure arguments, which is a valuable type of thought process to have for a career consultant" or "... and then I studied Poetry to learn how to become economical with words, which is important in presenting information, a key skill of consulting" or whatever.