Any where that WiFi is available. There are no restrictions.
Yes, you have to be connected to wifi when you want to FaceTime with people. They need to be connected to wifi as well, so text them and tell them you're going to Facetime them and to turn on their wifi.
The fact that your other laptop can connect to wifi is irrelevant to whether or not you have disabled wifi on the laptop that is reporting that wifi is disabled. Go into your settings and make sure you haven't inadvertently turned it off.
No.
No...you don't need wifi for the American idol app for iPhone.
yes, you can just use wifi access to use the Internet on your iPhone
yes
yes
ATT recently (Sept, 2014) announced that it will introduce WiFi calling for iPhone in 2015.
“How do I get wifi for my IPHONE, I already have internet service at home but it's not wireless”
You do not need to turn it on as it is software that is included as part of the latest iOS updates. You do need to ensure you are within an wifi network in order to use the service.
Yes, you can use your iPhone 3G(S) to access the Internet if you have an available WiFi connection.