I don't necessarily want to volunteer to be the person in charge of the brief, but maybe I can help us get started?
PRELIM FOUGÈRE BRIEF
Create a perfume containing notes of coumarin, bergamot/citrus, lavender/geranium, vetiver, labdanum and oakmoss. The opening should be bright, fresh, and green (think: fern!). The drydown should be spicy and herbal, in addition to the coumarin.
I tried to be open-ended but still specific enough that everyone would have some essential basic elements to hit (bright/fresh opening + spicy/herbal drydown). If nobody likes this, I'm totally ok with it, but ime it's easier sometimes to edit than kick off, so I thought I'd kick off!
I am not sure a brief has to be a list of ingredients, but maybe some can find it useful.
Anyway, I don't see any necessity for Labdanum in a fougère.
If you want to be schematic, you can say that Labdanum is typical in a classic chypre structure, but not in a fougère.