when lookign at teh meaning of teh word: succesor states. it would mean the Factiosn divided under Alexandros's generals. so all i could think of are:
Mcedon, Seleucids, Ptolemoi. and all other 'original successors' are gone by the starting time.
i would say Armenia, Pahlava and Bactria arent successors. mainly because they "weren't around" when the successor dived the lands.They've just broken free years after.