Yes, Moto C comes with removable battery.
No. You can use only one sim card on 4G mode in this phone. You need to use 4G sim card in sim card slot one. Second slot shall use 2G sim card.
Yes, you can. But right now back panels are not available in stock, since the model is just launched.
No. Auto Call Recording is not available but you can download Auto Call Recording apps from the google play store and can do auto call recording.