Before I did any planning outside of the pink (or blue) area I would cover the property with red, crimson and white dutch clover seed and simply watch for a year. You will learn a lot.
Does the little patch in the upper right belong to you? The one that's overgrown and green looking? If so a walk through there could tell you much about existing species and growing conditions.
Any indicator plants? I expect plantains and lambsquarters.
I love the idea of a central pond with hugelkulture beds forming an L in the SW corner and a 7 in the NE. Could switch that up depending on the wind.