Yes, Gionee X1 does have support for VoLTE.
Yes, Gionee X1 does have a LED flash for the selfie camera.
Yes, Gionee X1 does have support for VR.
No. Gionee X1 has 2 dedicated slots for the Sim cards and one dedicated slot for the memory card. You can expand phone memory by up to 256GB with the help of the MicroSD card.