[villagetinker]

I agree with the above about getting ARC approval, and based on my own personal experience, DO THIS YOURSELF, do NOT rely on the contractor to do it. Since you have talked to some contractors, make your own sketch. If you line in Sumter county, you can go the Pinellas Plaza (copper topped building), and get a copy of your plot plan, you will need this for the ARC review. You can sketch the proposed location of the stacked walls. As I recall ARC was not concerned about the plants. They are concerned with proximity to build lines, property lines, and any other restrictions on the property, and the cover material.
Once you have ARC approval, you have 6 months to complete the project. Use the ARC document to open discussions with any contractor, and then take notes as to what will be done, what plants installed, and the covering (stone, mulch, pine straw).
As stated before on many threads, DO NOT PAY UP FRONT, if they absolutely requirement payment to cover plats I would not go more than 10% of the total. Make sure you discuss the type of plants, future maintenance (pruning, fertilizing, etc,), write this all down, have the contractor sign it with the cost.
Contact Seniors against Crime and check out the contractor.
NOTE: you will need to revise your irrigation system for the new landscaping. At a minimum, the garden irrigation will need to be revised for the new arrangement. Lawn zones will probably need new heads and adjustments, and possibly removal of some existing sprinkler heads. You make also need to install revised drainage, especially if you have downspouts in the area og the new gardens.
Hope this helps.