CS(major/minor) and/or ECON(major/minor) and/or SOCIOLOGY(major) and/or BUSINESS MINOR at Cornell?

Think hard about what you want to do longer term. Tough to explain a STEM GPA for an econ major if you're combining econ or soc with CS major or minor; spoiler alert, it's really hard to get a "good" econ GPA if your sched is stuffed w CS courses. If you want to do hardcore quant, hft, etc. than CS may be the way to go, but don't underestimate 3110 and algo; they're required for the major and they challenge most software engineers let alone econ majors with a tech/CS interest.

Econ is the most straightforward of these options for IB. It doesn't give you finance training (take it from another Cornell A&S econ major who prepped technicals the hard way from scratch w/o finance, accting, etc. background). And I'm cynical but don't do sociology, just don't, it's so fluffy.

I would argue that for the broadest IB and exit optionality Econ combined with an info sci or orie minor is gold. No need for the marketing, mgmt, etc of business minor, just throw in accounting and finance. If you play your cards right you can have a strong econ GPA by recruiting time with proof of your STEM chops via Info Sci or ORIE minor (or just take 1110 & 2110 which is what I did). That'll demonstrate your technical aptitude which can help set you apart from typical ugrad finance to ib kids and also open doors if you want to go in the prop trading, quanty hedge direction.