While it is possible that Coda was, in fact, based on a real person who inspired Davey, I don't think this game was a genuine attempt to reach out and get in touch with said person.
The
literary concept Davey is using by establishing Coda as a real person, including dates and locations for where they met, conversations they had, is called 'unreliable narration'. The entire purpose of works using such a voice to project the work is to fool the one consuming the media into believing things were real when they weren't. Davey hinges his entire performance on the idea that you, as the player, will totally buy whatever it is he says.
It is in this honesty and openness that we're pulled by our shirt collars all the way down the path he wants us to follow. If you've read Davey's
blog post following the meteoric success of The Stanley Parable's Redux, you'll see all of the telltale signs of things that Coda "suffers" implanted into what Davey weaves into the narrative of each game we play.
The major key which proves that Davey is an unreliable narrator, beyond knowledge of Davey's past, is the Lamp Post prop. "Coda" specifically asks him to stop putting lamp posts everywhere. When the very first one arrives, Davey outright lies and claims that Coda was using these, not him. We can't fully trust his recollection of events because Coda's final act was to show to us that Davey isn't being honest with us. His lines are spoken with such an enthusiastic conviction that we really do think he's telling us the truth the whole time. But he's not.
As an aside, I think everyone would appreciate if you were able to pinpoint where in the podcast they claim Coda to be a real person. It's a short podcast, but not everyone is going to want to sit down for 40 minutes to hear one aspect of the discussion.
