heres my view. first post n all..
your question contradicts itself slightly. In the first sentence youve stated "In a vacuum" but further down youve wrote " ...have more force to "push" air molecules out of the way". So to answer both questions (in a vacuum and in atmosphere) in a vacuum, the only particles there, are the ones you put there. so because there is no mass to create any opposing force then they would fall at a uniform rate (unless the objects were ridiculously huge enough to cause its own gravity but thats going too far lol) so because theres no atmosphere, aerodynamics pale into insignificance because there is no 'aero' for the masses to be 'dynamic' through. they would simply fall at a rate set by whatever mass is causing the gravity, namely a planet
In somewhere with an atmosphere, then mass counts for a great amount, BUT! that doesnt necessarily mean a heavier thing falls faster than a lighter thing. eg a tank vs a tank with a parachute. you are ignoring a lot of forces that must be considered. is it windy? do the objects have the same aerodynamic properties? are they of similar shape? My overall guess would be that it is entirely dependant on what/who you throw... and what you throw it off
