Macs on wireless network can't see eachother
I have almost the same setup except that I have an E3000 but I'm not running Synergy.  My Macs can ping each other and share files.  I have IPV6 turned off.  You may have tried some of my suggestions but let see if any of them will help the cause.

I have file sharing enabled on both Macs and I can see my other on-net mac in the Finder Sidebar under Shared.  My Sidebar Preference under Shared allows connected servers and Bonjour computers.  With these settings, can either Finder see the other Mac?  It's good to verify this on both machines as a control.  If you can see either machine, you should be able to double-click to log in.

If not, please turn off Synergy then reboot each mac and see what comes up in Finder.

Make sure your E2000 basic wireless is set to mixed.

I did not use Cisco Connect opting to configure my E3000 manually and I'm not running WPS (WiFi Protected Setup).  If you are running WPS, temporarily disable it to rule it out as a potential cause.  On my E3000, I have configured any MAC access lists and access point isolation is disabled.

Temporarily disable any security option under Wireless Security for both the 2.4G and the 5G settings.  

Save router settings.

Reboot each mac and see what comes up in Finder.  This will help us see if this is a Mac, Synergy or Cisco issue.