Do you need to make a starter with a 100% brett beer?
Yep - most sources recommend lager pitching rates.
I've read (mostly on other posts in this forum) that Brett produces the most "funk" under stressful conditions. So if the purpose of all Brett beer is to really experience Brett's full character, wouldn't it be better to under pitch, at least slightly, to encourage ester production?
If you want funk, just pitch brett in a mixed fermentation.
When used in primary fermentation, brett needs to be treated as you would sacch. or it won't attenuate. Adequate pitching, aeration, temp. control.
Per C. Yakobson's paper, increasing acidity of the wort will yield more flavor compounds from the brett, but it may not be the funky flavors you're expecting - more along the lines of esters and phenols produced with belgian strains.