Furthermore, Uber is a public company now, and there is (as far as I know) no outstanding lockout period for employees. IF anyone has outstanding options, that are subject to a (most likely) 90-day exercise window, they can be exercised and immediately sold.

The typical "exercising of an option for an illiquid asset which will be taxed as if it's liquid" problems with start-up stock options simply don't exist in this case.