No. You cannot record 4K videos with the Oppo F7. Maximum resolution of video recording is full HD.
No. Oppo F7 does not have the Vooc charging support.
No. Oppo F7 has a mono speaker.
Yes, Oppo F7 does have the face unlock.
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.