Unless the axle is rubbing against something, it is not the problem. Your guesses sound good. A CV joint will start making noise if the boot is torn and dirt gets into the joint (this is very common). A wheel bearing has a rubber seal that is less likely to become damaged, but a reputable brake shop should inspect the wheel bearings when the brakes are replaced or inspected.
Another thing to check is the wheel wells. If you run over some road debris, some can get caught in your wheel well and rub against the tire. Check all four wheel wells, but especially the front wheel wells.
