I'm not an LG Stylo 2 owner, so I've only touched-on the general thoughts/questions in here, so I've no personal experience with rooting this specific device.
If the bootloader is indeed unlockable and you're able to flash custom recoveries (not sure if there's one available for this device or not) or better yet, the boot image, then you've got a good chance of rooting it without needing any "king"-related rooting method.
Modifying the boot.img to support/include root takes some knowledge / work, but is not insurmountable--unless there are other demons/gremlins running on your device that don't like things being updated...