Unless you know what they are, no there's no reason to be messing around with them. If Wifi works then all the settings have been provided correctly by the DHCP server. Which in most cases is your Wifi router, or access point. So there's no need to change them.
As for the Facetime notifications, you can go to Settings->Notifications->Facetime and make sure its set to on in the Notifcation Center. You can then configure the type of alerts and ringtone you want for it.