You have a lot of misconceptions…
I don’t know where you get the notion that Stanford’s CS has been “watered down [with] liberal artsy/humanities influence”. Harvard is indeed a STEM powerhouse… its engineering is a tad weaker, but the rest of STEM is on par with MIT, Caltech, etc. MIT is not only “pure hardcore academia”… it ranks pretty damn highly with its own entrepreneurship and start-up culture.
All 4 of these institutions would be outstanding for you… there is no right or wrong here. But please don’t base the decision on misconceptions and outdated stereotypes.
That said… with those interests, I would recommend Stanford or MIT.