[notbitter]

terminology around this issue can be VERY confusing

You are not making it any simpler by redefining "control" in this theoretical way. You are making some very naive assumptions about independence: you'd be much better off treating the investors as a single voting bloc, which is what the usual sense of "control" assumes - and if there are multiple founders you should assume that serial investors are very sophisticated at splitting them.

A good followup would be to go out and actually measure the distribution of voting outcomes rather than making a strong claim based on the most tractable assumptions you can find.