Yes, LG K9 Candy does have the FM radio.
Yes, LG K9 aka LG Candy is a 4G mobile phone.
No. LG K9 Candy does not have the fast charging support. But if you charge with the original charger and cable which is supplied, the phone gets charge very quickly.
LG K9 Candy has 1.3 GHz Qualcomm Snapdragon 210 MSM8980 processor.