Yes, LG K9 Candy does have the removable battery.
LG K9 Candy has Qualcomm Adreno 304 GPU. Which has a frequency of 400 MHz.
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.
Yes, LG K9 aka LG Candy is a 4G mobile phone.