There is not restrictions in terms of ramp rate, as far is something "normal", we didnt test the part with a 10s ramp rate or non-montonic supply rate.
As far as I remember, the only restriction is to connect GND before apply power to any pin.
Obviously, we should recommend a supply to guarantee that under any condition the part will be stressed... If the delay between supplies is within ms, not major issue.
Regards,
Miguel