I think the point is to recycle soil nutrients so I would research nutrient catch plants and test your soil for the nutrients you need. I agree with your thought to use native plants, it is better for the insect population and they are adapted to your environment. For me its all about low inputs. I also have a small yard and love permaculture ideas. I just adapt and take what works. Hope that helps.

We made a few raised beds and to offset the cost of bringing in soil (and who knows what with it?) we filled the bottom of the bed with thick layers of straw... probably a third of the way up beds that are a foot high or a little more. Then in fall we gathered up all the leaves in our mower bag and dumped the rest of the bed full of the chopped up leaves. Added the little bit of compost that we had to it and left it til spring. The worms and soil beasties did a wonderful job of working it for us and we discovered a happy thing: we had accidentally made the best possible bed for potatoes and carrots since they both love phosphorus which all the leaves provided. Sweetest carrots that we've ever grown. It was nearly free soil other than the straw. And now, a full year later it's just wonderful loamy soil that really holds water well.

Another thing to consider for beds if you have patience. Get a load of wood chips...often tree trimming places will give them for free and pile them up wherever you want a garden. Wait. They will break down into a fabulous soil, too. If you did this in fall, then the following spring you could dig holes, add compost and plant nitrogen fixers such as beans and peas. After that first year, plant away!