As of Feb. 25th, Columbia was still planning on having a "recruiting weekend" according to a professor in the department who was responsible for composing their first short list. Their plans may have changed since no one has heard about a fly out yet. They could just be a couple weeks behind schedule this year.
The threshold for consideration at the top 10-15 schools is certainly not 750. That's a little absurd. It's more like 700. Applications are considered much more holistically. Of course, a 750 would ABSOLUTELY pass the threshold for that one component of the application, but it is by no means a minimum to be considered. Even for finance I would imagine 750 is a little high for a "threshold".