Sounds like a good project although I doubt anyone here will have a pin out for these devices. Have you got much experience in electronics and microsoldering? The reason I ask is that the backlight and image voltage on the tablet screen will need to be a lot greater than the LG phone producers so you might have to design a separate circuit but it will be very hard on the battery.
The touch and image data circuits on the phone will also be different than the circuits on the tablet screen and I don’t know how or even if you could address this issue.