Columbia/Cornell STAT MA is too easy for you because you come from PKU. Stanford is too hard for you except you can get strong LORS.
However your GPA is low during the students from PKU who also want to apply stat/econ. I think it isn't hard for a guy get 3.9+ in double major/minor in Stat/math in PKU.
I think you have known the guy who was top1st in Yuanpei of Econ also apply for Duke ma last year, so due to the internal competition in your school, i think it is hard for you to be admitted such as Duke MA. Besides, i wonder that you can get very strong LORs from CCER. There are so many masters in CCER/GSM/ECON.