I like the layout too, but I want to bring up a point about the trees.
It sounds like you might have "iffy" soil for a pond due to the sand. Get the local NRCS office involved and see what they say. My issue with the trees is that not removing them means that you can't compact the soil in the pond basin, which might lead to leaks forming in those areas, especially after they die and the roots start to decompose.
re: The trees around the perimeter. Any soil disturbances or soil compaction under the crown of the trees could lead to the tree dying. Either cut 'em down during the land clearing process to give the heavy equip[ment room to move around or possibly have to cut 'em down later.
Other points:
Figure out a logging road so they can skid out the logs, or have a temp road for the logging trucks.
Have you ever seen uprooted trees? Do you have a place to put all the stumps?
Where are all the tops going to go?
That's all I got (for now).
