1-It is not normal,it should convert on cng when rpm reaches at 1700,and this fuel overlap time is adjustable.Any good cng technician can adjust it.
2-It is normal on cng.
3-It is not normal,get the IAC valve cleaned as it is not functioning.
Emulator cut off fuel injector only when vehicle operated on cng and fuel pump remain in working condition,therefore,it is recommended that fuel tank should be kept always quarterly filled to prevent fuel pump from burning.You can stop the fuel pump by installing a relay while vehicle running on cng,but it is not recommended for some reasons.