IF LG does the XL 2, they would do so in an ODM role with little, if any, input on the final product. Google isn't keen on artificial processing for their cameras... their HDR+ stuff is about as far away from what LG slathers on its pictures. The Nexus 5X, manufactured by LG, took pictures better than anything LG made for themselves. All LG did was physically install the sensor in the chassis, Google handled all other aspects.
Right, Google chose the sensor, Google chose the SoC, Google wrote the software, Google controls the camera.