After some catastrophic events, whenever I was smiling, the shape was altered, and took how my ex was smiling (very different facial structure) and triggered hallucinations of her face onto mine and other various emotions. It happens whenever (at various intensities) I mirror her smile.
[ETA: Yes, this is a response to "see and hear", which should perhaps be "see or hear", and because "we mirror and model their muscle movements" implies more than just vocals/sound.]
Even assuming that auditory information it is, I am unsure if it enables mimicry as much as visual information, which apart from being our predominant sense, it gives clear clue as to which movement led to which action/sound
We learn to read aloud, and there's usually a long transitional period of subvocalization. And even people who can read silently, if they want to very carefully understand something, often subvocalize it - even moving the lips silently. My conjecture is this process never goes away entirely.
> talking on the phone
Same mechanism. We hear the sounds and imagine ourselves making the muscle motions to produce such sounds.