1)
Why did they specifically mention their children and animals?
1.
Ramban: They mentioned animals, because animals need a lot of water, and children, so that Moshe should Daven quickly, since children cannot survive at all without water. 1
2.
Mechilta: The Torah is comparing a person's nimal to himself, inasmuch as it constitutes his livelihood - Someone who travels without his animal is in trouble!' 2