Yes, Nokia 5.1 does have the gyro sensor.
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.
No. Nokia 5.1 does not have the front camera LED flash but it does have the display screen flash.