Having met people from gaming in offline settings, it's really just a practice thing, but it does help to have a secondary derived name from their character that makes sense in public but isn't too descriptive. I imagine, in person, most of the JP livers use something like First Syllable + chan when talking to each other. In HoloJP, I've noticed Fubuki gets called "Fu-chan" a lot. Then you have the notable use of nicknames, which likely helps matters generally.I remember gura let slip a "Rebecca" while talking live to Ame, and Ina began forming "Tara" but stopped herself in time when addressing mooms, there's a point to be made about them using special names with each other and not their direct IRL names.
Or you can just generally give up even trying to remember their real name and your CoD buddy is now insult you all call him. Little Balls is a good dude.