XLR a good option for me?

I have asked this question of several audio dealers as well as a Nordost tech support rep. They all said basically the same thing. If you need a long run of cables (4 meters or more), XLR would be better as they can reject induced electronic noise better. But for short runs, they offer no real benefit although they certainly will do no harm.

The final sentence in this paragraph is problematic. Balanced connections are useful not just because you can run longer lengths but because they have less sonic artifact.

Put another way, if you have ever had to audition a cable for sound, that is the sonic artifact I'm talking about. Balanced has less of it, even if the run is only 6 inches. So this also means that you don't have to spend a lot of money on the interconnect for it to sound right. It simply has to be built correctly. Usually this means a twisted pair of conductors inside a shield, where the shield is pin 1 of the XLRs and also the tone arm ground.

if one side of the balanced circuit is grounded at the input in order to facilitate SE operation, I don't think there would be an inevitable problem with hum.  Do you?

No- of course, that's how all single-ended systems work, since phono cartridges are a balanced source to begin with.

If the input is an RCA connector, even if its used with a balanced circuit inside, the problem right away is that the user will be tempted to plug in a conventional RCA cable into the connection. The result will be hum, as the shield of the cable will pick up noise.

So if you see RCAs at the input, the only safe assumption is that the unit is employing single-ended operation. If its balanced, it will have XLR connections!