I hate having to complain about
anything in this quest, because I adored it. But I did catch a few things, so here goes:
HEAVY WARNING FOR SPOILERS
When first speaking with Darien in the Palace District to receive the quest, his pronounciation of "Alinon" has changed from what was used in Camlorn:
this happens again later at the tavern
https://youtu.be/pI3uKisoUhk[/url]
The lines available to use in dialogue with him beneath Gristmung Hold are identical to the ones already seen back in Sunport, despite
his lines being different:

Once inside the fort, but before Darien's ambient line about the library triggers, if we enter dialogue he will once again have his lines from Sunport (despite having already 'kicked down' said door a few moments ago):

Mannimarco's subtitles will fade out when his audio is only halfway through these:
disappears after "...nature?"
disappears after "...flesh."
Darien's comment once Mannimarco's image disappears refers to something I can't find a trace of, he says "Pets?" but Mannimarco doesn't, was it said earlier elsewhere?

At the end of our discussion with the Auroran, none of these options change what happens next - which I'm guessing is deliberate - and in the fraction of a second it takes for us to turn around, Darien, or rather, his 'passenger', has already slain all four of the Aurorans who were surrounding him, but to maintain the ruse that we are making a choice here, could the dialogue options have the red effect applied to indicate the choice is permanent?

Darien's sword changes colour in this scene - whilst sheathed its crossguard/pommel are gold and the hilt is wrapped in brown leather, then when in his hand or on the ground they're a dark steel with a grey-blue wrapped hilt:



Gabrielle wasn't in the Rivenspire questline... so why does Darien say she was there? (Gwendis was, but he's already listed 'those crazy vampires')

During our chat with Vanus back in Sunport, there's a discrepancy between the audio and onscreen text of his dialogue:
This happens for both scenarios, as it looks to be the exact same files used for this line.
If the Vestige fails to pull Darien back in the Temple and instead is given the farewell scene at the docks, the path of a Stirk Fellowship Soldier sandboxing in that vicinity will have him cut right through Darien's dialogue screen between you, or bump into the player's character and nudge them around. Could his path be relocated to prevent these interruptions? I had him cut through right as Darien finished delivering some very heartwrenching lines, and ended up laugh-crying:

Occasionally when entering dialogue with Darien in the Tavern scene his animation would glitch and he'd stare at a fixed spot to the left of shot while speaking. Exiting and re-entering dialogue would reset it and he'd resume his more expressive style.
Not an issue, but a request: in Laredon's House, is there any chance of opening the door from the bedroom into the smaller, locked room in the northeast corner and showing it to be a bathroom? As nod to one of Darien's lines in the Smolder Scrolls, since his attire in this scene is a throw back to Artaeum (and just where was he keeping those guards and boots anyway, or had he tracked them down along with the Lion Guard Captain's armor because of the memories potentially attached? Daggerfall Covenant pieces should certainly be obtainable if there are soldiers coming from Cyrodiil to assist the Fellowship.)