I agree with both AwD4869 and Vennowsah, Rum is definitely not Kansuke Yamato, Rum has to be Hyoue Kuroda and about the theory of Kir accidentally texting Rum instead of Run, it's a possibility but then again maybe she meant to text Rum because she is with the C.I.A and she told the FBI that she'd give them any insight on anything she learns, so maybe that was her insight to share with them.