EMI ≠ feedback, they're completely different things and don't sound the same, and the terms can't be used interchangeably.
Balanced cables/XLR don't reduce feedback, they help control noise. "
Audio feedback" AKA "feedback" on Wikipedia will help explain.
The ground-lift has nothing to do with EMI or feedback either. It's "lifting the ground" of the cable going to the modeler so 60-cycle hum isn't passed through the cable from one device into the Fractal and from there to the electrical ground. That should stop the low hum (at 60Hz) caused by a ground-loop, which is only happening because whatever the Fractal is connected to can't reach the ground as well as the Fractal can; there are multiple reasons that could happen but the important thing is that the Fractal has the ability to try to reduce the problem. See "
Ground lift (audio)" for more information, or search the Internet.