Rooted vegetation will grow on sand, gravel, mud, in between the rocks, etc. Pretty much wherever it decides to grow.
Your RES will probably like the manufactured sand. I put 50 1.5"-3" in my pond on the 24th of June. A few of them are now working at bedding on crushed limestone 1.5" surface material in less than two feet of water.
It's rather comical watching them chase the FHMs away from the beds. RES don't take any BS from a minnow. lol
Now would be the time to spread some crushed rock on those areas next to the beach that you have circled in red. It will give your sunfish an alternative to the beach for making beds. Might improve recruitment if there's going to be a lot of little feets pitter-pattering in the water on the beach.
Nice looking deal you've got going there. I look forward to seeing it full of H2O.
