Yes, Oppo F11 does have the support for the face unlock. It also has a fingerprint scanner.
No. Oppo F11 does not have the front camera LED flash but it has display screen flash.
No. Oppo F11 does not have the NFC sensor.
No. Oppo F11 does not have Dolby sound support.
Yes, Oppo F11 has dual 4G sim support. You can use 2 sim cards on 4G networks at the same time without any trouble.