The Cat Dilemma

I have a real cat dilemma, and I need help making a decision. About five years ago, I started volunteering for the local humane society. At the time,  I told them I would foster animals, but I only wanted to foster cats, because I felt I was less likely to adopt every cat that came into my home. (I've been more of a dog person all of my life; probably because I never had a cat as a kid.) Three or four months ago I took in four foster cats but one of them stayed for only a week.  The owner showed up looking for him. The other three are still with me due to overcrowding at the shelter. Since they've been here for so long, I made the mistake of letting them bond with me. Meet Napolean;

Napolean's owners dropped him off at the shelter saying they were moving. He's a sweet cat and likes to ride in the car. When I take him to the vet, he goes in one of those cardboard cat carriers. I put it in the front seat and open the top. Napolean stays in the carrier and sight sees while I drive. He's had a number of health problems.. The vet at the humane society got nowhere with a diagnoses, so I took him to my own vet and paid for it. When I first got him, he scratched the outside of his ears until they bled. We finally got that cleared up, but he throws up his food all the time. The vet has narrowed it down to either allergies or a blockage somewhere. She's going to test him for allergies.

Meet Josephine:

She came to me with the name of Ami, but I decided Napolean needed a Josephine. She's the smartest and most affectionate cat I've ever met. I decided I would adopt Josephine.

Meet Bella:

Bella was afraid of everyone until a couple of weeks ago. She suddenly started cuddling up to me, and she isn't afraid of the dogs anymore.

You might as well meet Shiloh:

I adopted Shiloh when I first started volunteering.

So here's my dilemma: I don't have the heart to take them back to the shelter now that they're settled, happy and think we're their forever family. Nobody will adopt Napolean, because he's black and has health issues. I want to move back to California next summer, but how am I going to transport four cats, four dogs and an elderly mother who won't fly? 

If you have a solution for me, I'll give you a cat and a dog. I'll even throw in the elderly mother.