About immortality type 4 for nuova shenron:
short of agreed, but it would be limited since he needs omega shenron to give him evil energy for him to revive
About immortality type 8:
i agree on immortality type 8, but it would not be combat aplicable as they would need the dragon balls to be overused to get revived, so it would also be "limited" immortality, and it would also be type 4 just like nuova, type 8 is having other types of immortality as long as something exists to grant it, this being the dragon balls, so it would be:
Immortality type 4 and 8 (Not combat aplicable, Every time the dragon balls are overused the shadow dragons will appear due to the evil energy accumulated in them)