Major/Degree for Finance

I am attending UChicago next year and only recently gotten into the idea of finance. I want to break into IB and eventually get into VC down the road. I am thinking of double majoring in Economics and a hard science (molecular engineering, bio, math, etc) since UChicago's economics program is obviously top, but I want the STEM background to be able to specialize in VC. 

First of all, do you have any recommendations for which science to pursue if at all? Also, if I double major, does it matter if I end up choosing my BA in Economics or BS in the science since I can only choose one degree? For the latter, would getting an MBA later be effective or plausible?

Thank you