A company like Concord Pacific might be interested in this site, it's sort of in line with their other projects and would expand their presence beyond Vancouver, Toronto and Calgary. A big developer that's new to the city with something different to offer might have better appeal than a local company that already has projects in other parts of the city.
Finding a component that is of "national" scope is problematic. It would be odd for a developer to propose a museum or gallery without the cooperation of or direct collaboration with the institution, so if any of these involve a museum like Science and Tech, there would have been some dealing going on behind the scenes.
Something like Washington DC's
Newseum would be a great fit for Ottawa — dynamic and contemporary, interpreting history as it is happening