Apple Iphone 5c repair help/ advice

[rip-it-up]

Hi guys, Ive damaged my bro's iphone 5c and wonder if anyone can help me.

Basically Ive damaged the fpc connector for the power and volume keys, I only bought one replacement fpc plug and when soldering it i lifted 2 pins from the new fpc plug, (pads on mobo are fine.)
Im waiting for a replacment but the old plug seems to work ok, for the power and volume keys, but i get a message saying this accessory is not support with nothing connected, (which im not really concern about i guess its just because of the missing pins on fpc)

My issue is that the phone will not charge but the iphone will display the battery and lighting sign when plugged in suggesting its charging but the battery symbol will be low red not matter how long it will on charge.

My questions are does the screen assy need to be connected for the iphone to charge? grounded etc
What actually need to be connected to charge the battery.

I think its worth noting that when the iphone had power the on off button work fine even with the original broken plug.

thanks all