The general structure of the rules will be the same as for v2; it's just in a different place (GLobal Rules) in v3, instead of Network Monitor.
I agree that the Network Zone is a little different to set up. I'm not at a v3 machine right now, but I think that the firewall Stealth Wizard will help make you visible to your local network, which should help with Wii. This should automatically create some Global Rules for you, based on what you tell the Wizard. That might make it easier for you.
However, I'd remove from Global Rules any that you have "tweaked" into existence, as they're obviously causing you problems now...

Once you've done that, then run the Stealth Wizard to set up the LAN.
LM