A:Answer Yes, I believe you could, but you would need to use an adapter cable(RCA to spades for example, which you can get from Amazon) if you're trying to connect a speaker with standard wire terminals/binding posts.
As has been said, the rear surround speakers connect to the system using a cable that is plugged into the subwoofer, the cable is plugged into the output ports on the back of the subwoofer, the cable has a single-ended RCA type connector on both ends, there are two separate cables, one for each rear speaker.
I'm not sure which speakers you have in mind to use as rear surrounds, but the included speakers have two drivers, one front-firing and one up-firing which is what gives the Dolby Atmos effect. Also, I don't think it would be a problem, it should probably be sufficient, but I'm not sure how much power the subwoofer puts out via the RCA outputs to power the rear speakers, but it is made to power the small rear speakers which are included, and probably to a matched volume level, so it might not work well to power full-sized speakers or large dipole speakers, I would check the speakers' sensitivity rating and probably stick to 4-inch drivers myself.
