If these pants hit you at the ankle (as on the model), I would avoid flats, unless you are exceptionally tall. Wearing flats with ankle-length pants can make the legs look short.
You could wear booties, but I would make sure that the shaft of the booties is high, very near the hem of the pants. This will help keep the long line of the leg.
I'm not sure about a wedge; I've never worn them and do not know how they would look with ankle pants.