The three bikes you mentioned have a mix of 3 different price points of Shimano components. That should be reflected in the price your seeing. Also, I don't believe the Specialized (just from web specs) has mounts for fenders/racks. that may or may not be something of interest to you.

You did mention fine gravel trails. perhaps you also want to try a steel bike to see if you like the feel of steel over Aluminum. I do. I prefer my Specialized AWOL over my Felt Z100. I wish I would of grabbed the Kona *****-Tonk instead of the Z100. good luck!