This has been a fun question to think about.
There is something about rhetorical analysis that seems to invite triangulation. The classical ethos-pathos-logos, the more contemporary author-audience-subject, and Nelson’s player-narrator-protagonist.
These schemata are usually presented as points connected by lines, but I think sometimes these lines might be more accurately depicted as vectors. In other situations, there may be no direct connection at all between two points.
The narrator may be a point of connection between player and protagonist, but they can also be a point of estrangement. The player usually issues second-person commands to a narrator who is not themselves the protagonist. They presumably interpret and transmit the information along, but players generally do not know what this translated message is. Sometimes there are errors in translation–is it the narrator or the protagonist who rejects the message?
I think most of us have typed out a perfectly reasonable command, only to have it misunderstood. We blame the parser, which is mechanically accurate, but rhetorically it is an estrangement between protagonist and player. Some authors have exploited this divide by implementing unreliable narrators. The outcomes can be very compelling. This may not be fourth wall play, but perhaps it is its friendly neighbor.
In-character narrators are a different situation, but perhaps some level of estrangement is inevitable. I’m not familiar enough with the tactic to say.
In a typical case, the player enters a sort of brain-in-a-vat situation, only they are accustomed to seeing the vat now and then. Suspended is quite good at hiding the vat, ironically, since it is essentially a brain-in-a-vat story by design.
I appreciate the thread, the lists, and the comments, very thoughtful stuff to read on a Saturday morning.