|Lobo: Cannot die. ergo he cannot become a zombie.|
|Poison Ivy: Could the zombie plague survive Ivy's blood?|
|Solomon Grundy: Catches plague, dies and comes back plague free.|
|Clayface: Not sure if he has DNA.|
|Danny the street: Ditto|
|Doomsday: He would die and come back with a resistance.|
|Swamp-thing: I assume since Man-Thing was immune.|
|Captain Atom: because he's living energy.|
|Deadman: He's already dead.|
|Gentleman Ghost: He's a ghost.|
|Mogo: Same reasons as Danny the street.|
Mr Freeze: (Maybe) Not sure if zombie plague could survive the freezing temperature.
Harley Quinn: (Maybe) Since Harley is immune to Ivy's poison blood then it stands to reason (if) Ivy is immune then Harley probably would be too.