Should, on most discrete graphics cards (like yours) the output connectors are treated like discrete outputs meaning each one can run their own display.
As for mixing cards for multiple displays it should absolutely work. You may need to fiddle with the Nvidia control panel, but it should work without hassle.
[IMPORTANT] The major concern you should run into is your power supply. You'll need around 600-750 Watts or better to feed those cards in full use. If your system starts to shutdown randomly while gaming, chances are your power supply isn't putting out enough amps/watts.