I have cats and a husky mix, I believe the introductions go easier when introducing a dog that has had regular encounters with cats since being a puppy, I introduced my pup when he was very small. We already had 2 resident cats.
As far as pooping and crate training, You should be potty training your pup in conjunction with using the crate. It should be big enough for the pup to lay down and turn around in easily, but no bigger than that. If the crate area is too large, the pup will poop in one corner and sleep in another. They do not want to soil themselves. We bought a crate that was for "Life Stages" it had an adjustable divider to give more and more room as Dante (my puppy) has grown.
here are some good websites on tips for potty training and crate training, the crate should be a happy place and not used as a punishment:
On housebreaking: http://www.humanesociety.org/animals/dogs/tips/housetraining_puppies.html
Crate Training: http://www.inch.com/~dogs/cratetraining.html
You can bookmark things like those for your future reference, and It's good you're getting information now before bringing a baby dog home