I was actually surprised that during Covid I saw on Amherst socials where they profiled students that had internships and I recall at least one interned on Wall Street and a couple at top investment companies. Maybe one was your kid @alohahonu 
Also, the Loeb Center on campus is incredible in assisting students connect and obtain internships. They also bring alum back to campus to connect with students and in the financial sector I remember one from Fidelity came last Fall. Although my daughter isn’t an Econ major at Amherst, she landed a nice internship through their strong alum network when we thought all hope might be lost due to Covid.
The reality is that you can’t go wrong at any of the schools mentioned. It’s going to be what you do with all they have to offer once you are there. I wish you the best!