Kinda hard to see what's going on but i think the lead with two wires is for programming the ESC.. The lead would be removed for normal flying and would be fitted only to connect to the Castle Link USB dongle. The loose lead with three wires appears to be the ESC throttle wire which will plug into the FBL.
I dont see a BEC wire but that would usually go to the battery port on the FBL as you suggest (or another spare port if the FBL has no dedicated battery port)