Can I Use the XLR Input and RCA Output (And Vice Versa) With My 1723 Subwoofers?

Unfortunately, no.

The RCA (or XLR) output is a direct pass-through of the signal on the corresponding input. But there is no XLR to RCA converter.
You could use a XLR to RCA adaptor if that's something you really need, but you'd lose the advantages of the balanced design of the XLR. Feel free to reach out to sales@arendalsound.com if you have any questions.