Here is a quick sketch calling out potential materials for us to start looking at. Here is the website link to one company that does pervious paving Grasspave and Gravelpave:
The grasspave is what i was thinking for the grassy moguls in the kids playground and the gravelpave would be good for the main paths b/c of ADA and bikes.
Also another product that may be cool for the paths and potentially the shaded area around the centro (but not the playground) is Grasscrete (see images below). I love the pattern. http://www.grasscrete.com/