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.
No. Moto C does not have the fingerprint sensor.
Yes, Motorola Moto C comes with Android 7.0 Nougat OS out-of-the box.
Yes, Moto C supports OTG connectivity.