No. Oppo F7 is not a 5G phone. It works on 2G, 3G, and 4G GSM networks.
No. Oppo F7 does not have the NFC.
No. Oppo F7 has a mono speaker.
No. You cannot record 4K videos with the Oppo F7. Maximum resolution of video recording is full HD.
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.