I forgot about the palm tree roots. Yes, I agree you wold want to fill your planting area with your above planned mixture. I wouldn't leave the sedum in the pots though, that will not encourage them to spread their roots out. I would just plant them directly into the mixture. I look forward to see how they do for you.
Love the photo of a mature succulent garden. Living where you do you can grow some very interesting succulents outdoors.
Please keep us updated on your progress, what a great gardening adventure you are beginning.
