OP, you asked about NU, Columbia. You got some lower grades in an easier track. Yes, these courses were required for that major in cc. But that doesn’t make them the level of rigor NU or Columbia expects. And doesn’t wipe away the lower grades.
NU and C will be looking for your rigor. Yes, “harder and more challenging” They’re rigorous colleges, tippy tops, with fierce competition, and expect their admits to be ready to hit the ground running. Ready. Tested, at high levels that correspond to the level of difficulty at an elite.
So just think about it. You can finish at any good school and, (as we often say on CC,) then look to an elite college, for grad school.