Goofs

As the family are leaving their native pond, they are flying towards the rising sun, which would indicate they are traveling East, not South.

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.

That is humor, as practiced by cartoons since time immemorial.

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.

Artistic license. Movies are not meant to perfectly reflect reality. This is not real life, this is a cartoon.

Clouds are actually just water vapor, so the ducks could not have worn them like bath bubbles as they pass through them.

Artistic license and suspension of disbelief - they might not be able to do that "in real life", but this is a cartoon.