I'm not exactly sure what you're saying. How, exactly, does it "play no role in the novel"? Ezri and Julian are two characters with whom the readers are invested. We care about what happens to them. We see a reconciliation between the two of them that has been a long time coming. How exactly is that not playing a "role in the novel"? It's a part of the on-going story of all of these characters! I guess I'm just having a hard time figuring out what parts of the novel you think "play no role," and what exactly your criteria are for inclusion in the "role-playing" parts of the novel.
You say that the things the novel talks about have "no bearing on the events of this novel." I see it differently. I see these happenings AS the events of this novel. I think it can't be studied in isolation. This novel is a part of the on-going story of Deep Space Nine and its characters.
I suppose this is another basic philosophical difference, then. To me, anything that can be removed from a novel without affecting the outcome should be removed. Chekov's Gun
. Their making up served no purpose to the plot of the novel. Nor did the mentions of Quark's financials.
Now, let's say in book #2 of The Fall, Julian and Ezri must work together to foil a dastardly plot by blah blah blah. That's where you put the stuff about them making up. Because that's where it will serve some purpose to the plot! Yes, I want to know how these characters are continuing their lives, but I want the accounts of their behaviors to matter to the novel! Otherwise, why not just create a daily diary for each character and call that the next novel?