These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Fridge Logic: Dara is responsible for setting in motion Brand's plans to obliterate the Pattern. Brand is responsible for setting in motion the invasion of Avalon by Lintra, who bears a child by Benedict who becomes Dara's grandmother. May be justified in that either a.) Chaos time is non-linear, or b.) Dara is a big fat liar.
Possibly Dara's faction was responsible - she does use the pronoun "we" a bit. Possibly she's a time traveller - about the only thing that doesn't happen in the series. Sadly, we'll never know.
Dara's conversation with the Logrus in the tenth book essentially states that she was in cahoots with the Logrus - and therefore presumably an adult - before Brand ever went to the Courts. Which means that the hellmaids' first emergence into Avalon predates the marring of the Pattern - Dara's existence being the consequence of the first while Brand's corruption or manipulation is the consequence of the second. The construction of the Black Road had apparently been going on for much, much longer than Corwin always assumed. Either Dara was an adult before she was conceived, or - and this is more likely - the invasion of Avalon was part of some earlier scheme in Chaos and the Dara-Brand connection was an attempt to exploit the success of that earlier established foothold.
Magnificent Bastard: Oberon, and several of his children try to match him in this. To the point where Corwin deduces Oberon's presence simply because no one else could pull off a Gambit Roulette that well.
Mary Tzu: Some might regard Benedict's proclaimed abilities as... over the top. Or at least regard Corwin's opinion of him as evidence that Benedict has his brother(s) completely psyched out.