When the elderly heron gets the pan and puts it in the water, there is clearly nothing in it. After the Mallards have gotten in, Mack pulls out a partly-eaten fish that was not there before.
The fire extinguisher would not have been set off from the weight of a duck as most fire extinguishers have a pin that must be pulled and two handles that must be squeezed together with considerably more force than a duck's weight, to prevent accidental discharge.
Clouds are actually just water vapor, so the ducks could not have worn them like bath bubbles as they pass through them.
As the family are leaving their native pond, they are flying towards the rising sun, which would indicate they are traveling East, not South.