A:AnswerDepends on the terms you purchase them on, how long you've had them before needing to replace them and as far as replacing one of them, you might have to shop on Amazon or Ebay to be able to replace one.
A:AnswerYess they are compatible with both iOS and Android. You would just have to pair them using your Bluetooth setting. iOS would not auto pair when the case is open like an Android device would .