You don't have faith in their Statler and Waldorf depiction of their relationship?
As for whether they're alike or not, I think they're actually very different, but with very close similarities. I don't think either have sticks so far up their asses that they'd step over the banter line and into direct insults. I honestly think they'd make a good show of making it look like they hate each other's guts with their kind of 'faux, throwaway insults,' but are actually just jabbing at each other playfully. This is just speculation, but I think, under the surface, they'd have great respect for each other and the worst they'd think would be that their ideals are noble, but wholly unrealistic.
Of course, I'm sure Bioware has better banter-insults than, "Ooh, your hat looks silly."
Maker help him if Vivienne is an LI:
Dorian: Why Vivienne, is that a smile on your face? Has the rest of your wardrobe arrived from Val Royeux? Or perhaps there's some poor servant somewhere in the hold crying into their breakfast?
Vivienne: Well aren't you inquisitive this morning?
Dorian: Not as
inquisitive as you've been lately. Have my eyes deceived me or does Madame de Fer have a heart made of something softer than cold iron?
Vivienne: Jealous, Pavus?
Dorian: Of course not. Like my master always told me, there's no accounting for taste.
Vivienne: To think that such sage advice could come the lips of a madman.
Dorian: I see that our leader's tender ministrations haven't dulled your insistence on getting the last word.
Vivienne: The day is still young.