This is the bare minimum firewall modifications you need to make to get remote shutdown working on a Windows 2012R2 Active Directory domain working. Open up the Group Policy Management snapin. Add a new Group Policy Object, call it Remote Administration Firewall Rules.
Edit the Policy: Computer -> Policies -> Administrative Templates
Network/Network Connections/Windows Firewall/Domain Profile
Windows Firewall: Allow ICMP exceptions: Enabled
Windows Firewall: Allow inbound remote administration exception: Enabled
I would only allow from one ip address, that of a dc, for now anyway.
Link the policy to the OU that contains the computer accounts that you want to apply the policy to.
You should be able to use the shutdown /i command on the allowed server and reboot (or shutdown) the doamin computers.