Hi Todd,
Typical home stereo brand, Klipsch. It’ll probably work, but not really made for DJ-ing. More of a home entertainment system bit.
The 10″ KRK sub would be a better match to your Rokits. Although technically you could hook up any sub to any set of top end speakers, but in practice staying with the same brand (and even same series) is the preferred way to go. They will be best tuned to work as a combination.
The XLRs are really not that relevant if you are using them as near field monitors (i.e. left and right of your monitor and equidistant from each other and your ears) without running long cables and/or passing lots of other gear (potential sources of interference picked up in a RCA cable). But it makes for a better cable, better connector option, so I’d still used it if it’s there.