Yes, Nokia 3.1 Plus is a dual VoLTE mobile phone.
No. Nokia 3.1 Plus has 2 slots for sim cards and a dedicated MicroSD card slot.
No. Nokia 3.1 Plus does not have the front camera LED flash but it does have the display screen flash.
Nokia 3.1 Plus has dual rear camera setup. The main rear camera of 13MP has f/2.0 and secondary rear camera of 5MP has a f/2.4 aperture. The front camera of 8MP has a f/2.2 aperture.
The Nokia 3.1 Plus is not the most competitive phone at its price level; not by a long shot. No matter how good it looks on the outside, it's hard to ignore just how much smoother the usage experience is with other models.
Overall, the Nokia 3.1 Plus has a vibrant display despite being of HD+ resolution, and the phone offers good battery life too. I even like the design, especially the aluminum back and soft rubberized finish.