Can't wait to hear how it turns out for you. I did a similar experiment where I did the primary fermentation with wine yeast (K1V-1116), then added Brett after the wine yeast finished. Half got Brett C, half got Brett B Trois. The idea was that the wine yeast would leave more for the Brett to work on than a beer yeast, resulting in a more intense Brett character. I don't have exact notes in front of me, but the numbers indicated it worked, with the wine yeast finishing around 1.020 and the Brett taking it down to the low single digits. Surprisingly though, the Brett character was pretty subdued. And despite the low finishing gravity, the beer didn't have a very dry finishing impression. My hypothesis is that the Brett fermentation, with that much sugar to work with, behaved a little more like an all-Brett primary fermentation, where you don't get the same Brett character. I also think the wine yeast is leaving something behind (esters, sugars, etc.) that takes away from the dry finish I wanted. Anyway, I think I need to experiment more with different wine yeasts and Brett strains to see if I can get closer to what I was looking for.