Moto G5 3GB variant has 2800 mAh battery. Which is sufficient to last the full day.
Yes, you can update this phone. However, this phone comes with latest Android 7.0 Nougat out of the box. So, you may not require to update the phone immediately.
Moto G5 3GB RAM dimensions are 144.3 x 73 x 9.5 mm.
Yes, Moto G5 does have Gorilla Glass Protection.