Nokia 5.1 has a 3GB LPDDR3 type RAM. It is a single channel.
Yes, Nokia 5.1 does have the fingerprint sensor. It is located on the back panel of the phone.
Nokia 5.1 has an ARM Mali T-860 MP2 GPU. It is a dual core GPU and GPU frequency is 700 MHz.
Yes, Nokia 5.1 has the Corning Gorilla Glass 3 protection.