Yes, Oppo F11 does have a 3.5mm headphone jack.
No. Oppo F11 does not have the front camera LED flash but it has display screen flash.
Yes, Oppo F11 has dual 4G sim support. You can use 2 sim cards on 4G networks at the same time without any trouble.
No. Oppo F11 has MicroUSB port.
Yes, Oppo F11 does have support for the fast charging. The mobile comes with VOOC 3.0 enabled the fast charger. It charges almost 20% faster than the regular fast chargers available in other mobile phones.