No. LG K9 Candy does not support NFC.
Yes, LG K9 aka LG Candy is a 4G mobile phone.
No. LG K9 Candy does not have the front camera LED flash but it does have the display flash. Which helps to take a good selfie during low light conditions.
LG K9 Candy has 1.3 GHz Qualcomm Snapdragon 210 MSM8980 processor.