Couple of things:
1) If the Brett C. is going to be your only yeast, you need to make a big starter. A 5 gallon batch needs a 4L (lager sized) starter if it's a 100% Brett fermentation.
2) Every time I've used WLP645 the beer eventually sours. I make a house saison that I pitch a vial of 645 into. 90 days in primary and about 30-45 days in the bottle and that beer takes on a distinct tartness. It gets stronger and stronger as time goes on. Just keep that in mind.
3) No steeping grains?
Everyone's always in favor of saving Hitler's brain but when you put it in the body of a great white shark, oooooh, suddenly you've gone too far.