Round or Square, and overall layout

All,
I have been working on a few landscape projects and here is what I have for idea so far?

1. I will be building the two retaining walls shown in the diagram. These will be build from cinder block then faced with stone. Any hints or suggestions there. The walls will be under 3' each. I tried to look up the NC builders code to see if I needed a permit. What an endless search that was? Any insight or links I can get the answer from. There will be 2' between each wall and stone stairs going into the main garden area. I was thinking of building an entrance over the stairs and putting a clematis on it? suggestions....

2. As you can see from the diagram I am thinking of putting a pond in the open area by the royal red hydrangea's. Again, my first landscaping project ever.

3. I am putting stone pavers from the back deck to the garden. Do you think it will be a major clash if I face the wall with stone? I plan on matching colors or should I make the walkway from the same stone? I wanted to use pavers because of their durability and lifespan.

4. As you can see the main circular planter in the middle is close to where I want to put a patio area. I was going to build this out of the same pavers as the walkway. My question here is should I build it circular like the planter, would a square patio area look geometrically odd ?

I have been working my fingers to the nubs with my wife on this project, however it is our first. The total area is 50 yards by 75 yards for our garden area. Any suggestions would be beneficial. You can see a picture of the ground on my other thread

http://davesgarden.com/community/forums/t/819443/

Thanks
Michael and Ei The'

I'll share my thoughts on a couple of your questions:

1. permits--my guess would be if they're under 3 feet you don't need permits. But if you want to be sure, the people to talk to are the people who issue permits. In most places, that's the city building department or something along those lines. I'm not surprised you didn't find anything state wide, it's the individual city that's in charge of issuing permits so that's who you need to talk to (and chances are you won't find much on the internet, you'll have to call them)

3. For the stones, I think you either have to do your best to match them (slightly different stone shapes is OK, but the color should match), or do something that's a clear contrast (either in stone style or color). What I'd avoid is something that's just a little off from each other, that's when I don't think it'll look as good.

4. You've got both rounded elements and linear elements in the design right now, so you could go either way on the patio. I'd do it however you like it best (or however it's easier for you to build it)

ecrane3,
Thanks for the comments. I started the retaining walls yesterday. Wow a lot of work. The area where the retaining walls go is going to take some major excavation. Here is my idea for the retaining walls. Plans are not to scale, however they give a general idea of my build.