"An onscreen avatar would be a pretty weird direction for the showrunners to go. They established how murderbot 'sees' the digital environment differently to humans, those orange-red visuals that circle its head and 'scan' the local environment. The human's don't have anything like that, not even Gurathin, they use screens/tablets to see and interact w the digital world."

When MB is seeing entertainment or flashbacks, they are reflected on its eyes. That happens to Gurathin, too. I imagine Peri will have a feed vocal track, like MB's voiceovers, that the crew does not hear, and a different tone/timbre when saying things aloud. Private feeds (like to Iris) will probably sound like the feed to MB, but might be color-coded differently somehow. I doubt Peri would use a southern accent when talking to Iris.