I don't think weathercocking comes into the equasion. As far as I know weathercocking is turning around the main gear.
In cross wind the tailplane is being pushed aside, causing a yawing moment into the wind.
The crosswind also has an effect on the wings in a way that the angle of attack of the upwind wing is different from the angle of attack of the downwind wing. This will cause a roll effect into the wind.
So if the engine on the windward wing would fail, the yawing and rolling effect would increase. So this will be the critical engine.