This is straight up false; Kong is the current Commander in Chief of the World Government.
He was promoted, he did not retire.
He was promoted, he did not retire.
Luffy will fight Sakazuki, but his fight with Sakazuki will have nothing to do with his confrontation with Imu sama.
The World Government would be confronted at Mary Geoise while the Navy will be confronted at Navy HQ. Ergo, the two fights are not connected.