It sounds like you have a solid mix of fruits,nuts, and perennial veggies. Plus I'm jealous of the space! [br]
My vote: Nitrogen fixers. You've got a advantageous mix to feed humans and animals. But only clover and grasses to feed the plants that a feeding the humans and animals. On the surface, and nitrogen fixers seem boring. But once you look at a few lists,there are some advantageous perennial fruit-bearing (or other purposes) options.
There are tons of "lists" online like the one linked below.
http://tcpermaculture.blogspot.com/2011/05/plants-nitrogen-fixers.html
A tree that's not on the list that will add some aesthetic beauty is the Eastern Redbud. Not certain how it'll accomplish in your area, but it's a really advantageous looking tree.
A food forest permaculture guy you may be interested in is Stefan Sobkowiak. He's Canadian, and but the concepts transfer just with different plants. He uses a simple "trio" layout for biodiversity. He uses the acronym N-A-P (nitrogen fixer - apple - pear/plum).
https://www.youtube.com/watch?v=bDog8MLFJtk
Source: thesurvivalpodcast.com