First off, please note that I am not in any way trying to bash you or your decision. You seemed genuinely concerned for Zoe and your family. I'm just trying to maybe help you see some things that could be helped...

Quote Originally Posted by 4theloveofzoe
Zoe continues to have behavioral problems. Soiling in the house. (Although she has gotten better.) She bites and playfully attacks my 10 year old daughters, when Zoe was meant as a companion animal for my 10 year old, Marissa who has disabilities.
How old is she? This sounds like normal puppy/adolescent behavior to me. Dogs play with their mouths; they have to be taught that this is not acceptable behavior. What do you do when she playfully bites somebody?

Quote Originally Posted by 4theloveofzoe
When the younger girls try to take her for a walk, she pulls hard. So they refuse to walk her. ANd has PULLED me hard enough to cause damage to my already injured arm (carpal tunnel syndrome).
I know (having a husky, a known puller) that teaching a dog to walk nicely on a leash is not easy. I also know some people on here do not agree with using these, but I think it could be worth a try.....have you thought about a halti or a prong collar? Though I rarely use them, I have tried both and both helped *significantly* with the pulling.

Quote Originally Posted by 4theloveofzoe
She dug HUGE holes in our yard, that made us got a warning from our landlord, that our lease was going to be cancelled. Which would cause us to become homeless and have no where to go.
Do you leave her outside unsupervised for long periods of time? Dogs usually dig because they are bored...I would think if she was only outside long enough to go potty or if somebody was out there playing with her and watching there wouldn't be a problem. I've also heard of getting a kiddie pool filled with dirt and teaching the dog to dig there instead of the yard (haven't tried it, my dogs don't dig).

Quote Originally Posted by 4theloveofzoe
I just think that we made a mistake about adopting a medium sized dog.
I personally don't think the size is the issue. It's her age and lack of training. The only issue that I think size could matter is walking on a leash...but let me tell you, my 17 lb schnauzer can pull harder than my 60 lb siberian husky...

Quote Originally Posted by 4theloveofzoe
I emailed the animal shelter that we got her from, and am waiting to hear about returning her. I tried calling before and no one returned my phone calls. Anyways... We just don't think it's fair to her to be cooped up all the time, because everyone's afraid to walk her because she pulls so hard.
I hope the shelter is not a kill shelter? Black dogs are usually the hardest to adopt out. If you are insistent on finding her a new home maybe you could try contacting some local rescue groups instead.

Quote Originally Posted by 4theloveofzoe
I've tried training her since we got her, and nothing has worked with her. She needs a professional, and where we live there are no professionals.
Have you contacted all of the local vets, pet stores, etc? There may be one that you just are not aware of.

Quote Originally Posted by 4theloveofzoe
We are looking at adopting a 10 month old small breed dog. He's already trained, and won't be a problem as far as walking him, etc.
I hope you know that training is a lifetime thing. You have to continue to work with the dog throughout its life to continue the training and good behaviors. Small dogs can have the same behavior problems that large dogs can have.

Whatever you decide to do, I wish you, your family, and Zoe the best of luck.