I use dwarf fruit trees and keep trimming the top so they bush out. I also like the fast growing ornamental ones such as crabapple and bradford pear. Most hawks will not land in the small trees, but prefer to perch up high to watch for food. I planted evergreen shrubs in my call duck pen since they like to nibble on everything... I also have lilac bushes and a few others that grew tall enough to be out of range for chickens to nibble on.
We have a great roosters and turkeys that watch and signal when a hawk is flying over. They actually can learn the difference between them and crows and buzzards which present no threat. Here we have crows which actually chase the hawks away. As long as chickens can dash for the coop they should be ok.
Don't know about eating the fruit since pen once housed your dogs. The chickens would sure enjoy them....
As far as grapes go we used 2 treated square posts and nailed a portion of cattle panel to them. Placed panel 2 feet off the ground and within a couple years the grapes had grown and vine up thru the panel and provided shade and cover for the chickens.
I also have seen where people placed 4 posts and nailed the panel onto the top of them. Growing the grapes up each post and letting them vine over the top. This works great also.