In order for your phone to vibrate during calls, make sure that the phone is set to vibrate in your TextNow ringtone options, as well as in the actual Sound settings of the phone. You can do this as well by hitting the volume down button on the back of the phone until it is on vibrate only.
When you are connected to wifi, the phone will not use your data unless the wifi signal drops. If you would like to ensure that your phone is only working on the wifi network, disable your mobile data. Just be sure to remember to turn it back on though when you leave the wifi connection, as it is required to receive your texts and calls.
At the moment, we do not sell iPhones, only Android devices.
As for your caller ID number, the name that shows up with caller ID is the name you have on your TextNow account. To make sure it shows up for the person you are calling, they must have caller ID as well and you must make all your calls through the TextNow application. :)