Yes lightbridge is 2.4Ghz, as is the Phantom 2 control board. You are correct, the lightbridge is for the FPV downlink. You will need to change out the 2.4 board in the phantom to a 5.8 and then get a 5.8 controller.
Will be great with the GoPro 3, but will not work with the 2.5k or 4k...