Yes, Oppo F7 does have the VoLTE support. Both sim card slots support VoLTE and you can use dual VoLTE at the same time.
Yes, Oppo F7 does have the 3.5mm headphone jack.
Yes, Oppo F7 does have the face unlock.
No. Oppo F7 does not have the LED notification light.
The Oppo F7 is a good upgrade over the F5 in terms of battery life and SoC performance. The selfie camera is also easily one of the best in this phone's price range, and new additions like the Sense HDR mode and AI Beauty work well most of the time.