You are not there yet. You are so far from being there that you did not ask a single question. I would suggest that you do something to get closer to "there" which will then give you specific dilemas and/or choices that you might need advice on for making. As Glenda the Good Witch said to Dorothy, "it is best to start at the beginning and then just follow the yellow brick road". Work from general toward specific. An example would be that you want a patio, then where it should be relative to other activities that exist or you want to exist (like near a door to the kitchen), then how big you want it vs. how much room you have,.... Choosing material is a resulting point not a starting point. It will be a matter of whether you are going to be wearing shoes or barefoot (around a pool? you don't want to pick up loose joint material on wet feet and have it in the pool, you don't want exposed edges that can hurt feet, you don't want something too hot to walk on), it will be cost driven to one degree or another, availability of materials, and finally the capability of your contractor (you in this case I suspect). OZ is a long way away and there are witches, lions, and tigers, and bears, and lets not rule out flying monkies. Surround yourself with good people and ask the right questions, and above all, make the commitment and all will be well. Commitment is often in the form of hiring qualified people. It often requires spending some money. Sometimes it can be done through hard work and determination. It never comes too easy or it is not much of a commitment.

Those are a lot of questions, but they are all very good ones that are not easy for people to find answers to. First, anyone who designs landscapes is a landscape designer. There is no criteria, licensing, or regulation(Oregon has some rules on what you can design without a license). There are horrible landscape designers, great landscape designers, and everything in between. There are landscape design associations and certification programs that are voluntary and try to establish a particular level of competency and professionalism. They also have dues and testing fees of its members which can make them a bit of an industry of their own in some cases. My belief is that some type of membership or certificate is better than none in that it shows some type of standard was met and/or a designer's commitment to becoming more competent and more professional. Landscape Architects are licensed professionals in 48 states. I believe it is Vermont and Colorado that they are not. The criteria for licensing is usually the same for most states, but there are variations. Typically, they require a candidate to pass a standard test called the Landscape Architect Registration Exam (LARE) which used to be six or seven sections that took three full days to take. It is slightly different now, but very similar. In most states they require a minimum of a Bachelor's degree in Landscape Architecture from an accredited Landscape Architecture program (I believe there are about 70 such universities and colleges that have accredited programs) to take the exam. Then you would also be required to work full time for two years under the direct supervision of a licensed landscape architect before taking the exam. That is basically six years of education followed by a rather tough exam. Whether an LD is an LA, or has a certificate, a membership in an organization, a degree, or has been taught through the school of experience, it is a very diverse field where one individual may be very competent in some parts of it and not so competent in others much like a good pediatrician might not be a great brain surgeon. So, you can not assume that any particular individual must be able to do "X" because they are called a "Y". This does not make it easy for the consumer, but it is reality. Your excavator guy has probably put in hundreds of driveways and does a good job. The problem is that your world is more than your driveway and having the foresight to make the driveway work with the rest of your landscape is probably not in his repetoire. It may be that the way the driveway is laid out and graded will be just fine with what follows. But, it could be a very limiting factor in what follows. Design/build is where you may find the best financial efficiency since the designing part of the operation is what drives sales in the construction part of the operation. It pays for a design/build firm to sell design work below what a design company would charge. The reason is, and I say this from experience, that once you bring a client through the design phase, they seldom want to switch to another company for installation. That means a high rate of sales in installation (where the money is). The negative is that the designer is working for the best interest of the company rather than for you. If you hire a designer, that person is working for you. Should you retain the designer to follow through the construction of the job, the designer is obligated to monitor the job for quality control and accept or reject all aspects of the job and let you know when the contractors have met their obligations for payment. This can cost you 10-20% on top of what the contractors bill. If a job is fairly straight forward, you may not need or feel like you want to pay your designer extra to oversee the project. Not all designers want to oversee projects because it involves a lot of responsibility and having to stand up to contractors who can be pretty tough. A nursery designer usually is for the purpose of selling stock from that particular nursery. Most contractors make the bulk of their money by marking up materials that they buy from sources that work best for them. The nursery the designer is working for might not be amongst the contractor's favorite sources which will be a conflict. This often means that you are limited to a smaller number of contractors who routinely do work for the nursery's designer or the nursery has their own staff installers. What this all means is that there is no easy answer. You have to talk to different people to find someone who matches your particular circumstances. My suggestion is that you work backwards. Find a similar style home with similar circumstances that has had this type of work done to it that appeals to you in a similar economic neighborhood. Then approach the homeowner by complementing them on the looks of their landscape and then find out who did it and what their experience was like. This should yield someone who is capable, local, affordable, and reasonable to work with no matter their title or educational background. I am an LA, by the way.

I interviewed quite a few int. designers. I hired one, and she was very good, but I didnt share her aesthetic. I paid her hourly with a "not to exceed" amount. She was also very busy, and I decided it wasnt working out, but she did have good advice. I found another firm that I really like. They are charging hourly, with a retainer. I would recommend starting with the designers as soon as you are in the planning mode with the architect. They may have some ideas that you may want the architect to incorporate into the plan. For example, the first designer suggested I add hidden electric blinds..so the architect amended the drawings so we could build these in. The second designer also had ideas and we had to amend the plans to accomodate these as well. They work in CAD, which is great. I also have a landscape architect. They can have input which you also may want to incorporate into the design.

Can you add some additional photos from within the yard? Its hard to judge how significant a slope you are dealing with and we can't really see the retaining wall. Some photos facing the house would also be helpful.