This post peaked my curiosity on the matter of Brett being able to break down some acids. I would imagine that some Bretts are more aggressive about this than others? For example, Jolly Pumpkin sours are generally not very tart (say compared to Sour in the Rye or La Folie). I don't have any experience with JP dregs, but I've heard Ethan Tripp talk about how their Brett is so aggressive that he keeps those dregs separate from other dregs beers.
I would assume just as a matter of genetic diversity some strains are more aggressive than others. However, my understanding is that like sacc, brett will metabolize available food sources in a particular order. That usually begins with consuming sugars and then starches before scavenging for other food sources like ethanol and whatever else it will consume. So if that is the case then I would expect the ethanol and acid metabolism will always occur with time and at least some of that metabolism may require a certain level of oxidation.