I can compile custom kernel , cm or even anything that can come to your mind but the question will stay the same how to flash it , fastboot was removed (not hidden) even if king root can give root access on this device it will be a temporary root that get lost on reboot, i have dealt with phones from at&t , metro , verizon and t-mobile , metro does not lock their phones or their bootloader (at least for the phones i dealt with) so i think it was zte decision to remove fastboot which is the only way to unlock the bootloader.