I have followed instructions for this. Using an iMac with Yosemite. Have a router and a dyndns hostname.
1. I'm no longer getting a 'wake up' button on other devices.
2. I can wake up the computer from within my LAN with an app like Mocha, but cannot wake it up from an outside address despite doing everything your instructions say. Following instructions to wake up to a specific computer in my LAN. Not sure what IP to use to try to wake up all in my LAN from outside but the specific computer wake-up method should work according to TeamViewer instructions.