The specific differences between RNAV 1 and RNAV 2 approval is the use of Flight director or AP which MUst be used for RNAV 1 but not for RNAV 2 which may be flown using just a deviation display.
Correct. Which is why an RNAV 1 approval includes approval for RNAV 2 unless the approving authority is incompetent.