No, you do not get the same amount of water if you drink two glasses of water mixed with ice tea. If you decide to mix water with other things water should constitute a bigger percentage. And you should not take tea and assume that it is enough and you do not need water. Your body needs that plain water. Check out more information http://www.livestrong.com/article/476159-can-i-drink-juice-instead-of-water/.
Technically yes. But remember, regular tea (other than herbal), coffee, alcohol, and sodas will also dehydrate you, so it kind of defeats the purpose of drinking to quench your thirst and to hydrate the body. It is best to drink plain clean pure fresh water.