Aw, what lovely pictures of sweet Disney girl! She so pretty.

I went to my trusty natural healing for dogs/cats book to see if I could find anything to help.
Looks as though your are on the right track.
Quote: Put gravy on the menu: one of the easiest ways to help your pets get more fluid is to moisten their dry food with a little water Or give them moist or canned foods which contain a lot more water than dry kibble.

Other quotes about/on water.
Pets with constipation are often encouraged to drink more because water lubricates the digestive track and and helps stools move more smoothly.
Tips from vets to make water more appealing.
Buy bottled water: Most pets prefer spring water to tap water
Add a little flavouring: Maybe add flavour by adding water left after boiling meat or chicken.

The other thing is fiber.
This is one of natures most powerful remedies. Found in generous amounts in products such as Metamucil and in grains, bran, fresh vegatables and canned pumpkin, dietry fiber is a superb digestive aid that can relieve constipation and diarrhea.

Please give your sweet little girl some kisses from me.
chris