Was the colliding object in the Guadalajara accident ever identified?
According to Boeing, there was no foreign object involved at all, and the cause of the damage was  an implosion of the radome due to differential pressure, caused by improper installation of a seal:

From AVHerald:


  On May 31st 2019 Boeing reported that a visual inspection of the radome did not show any evidence of a hard or soft body impact, no DNA material was found. Boeing concluded: "The review showed that an interface seal was installed around the entire periphery of the radome with no openings. This configuration lacked the approximately 8 inch opening in the seal along the bottom of the radome interface specified in engineering drawings and the Airplane Maintenance Manual (AMM 53-52-00) radome installation task. This opening in the seal is required to allow the radome area to drain and for equalization of pressure changes across the radome during flight. A review by our engineering team concluded that the lack of this gap likely resulted in differential pressure across the radome during descent which may have contributed to an internal collapse of the radome."