Oh my God, I turned off Standby mode just a few days back. Gonna try to keep it that way... Even though I set blocked IP's so let's go ahead and see if that actually worked in the first place.

Hopefully I don't accidentally update while testing this.
EDIT: It started downloading!

I instantly went to my settings to remove my connection then shut off my WiiU, so I'm going to try the OpenDNS method. I wonder why putting the IP's of the URL's in my firewall didn't work. I had to use a URL to IP converter site because the text boxes are limited.
EDIT2: Okay, OpenDNS isn't working either. Here's what I got going on for my settings.
WiiU connected to my WiFi and went to change settings.
IP: (The one that shows up on OpenDNS updater)
Subnet: 255.255.255.0
Gateway: 192.168.1.1 (Router)
DNS Primary: 208.067.222.222
DNS Secondary: 208.067.220.220
When I go to test, it fails... Connects to my router though.
Forgot to mention, automatic IP will keep downloading the update.