Update using hoplites and fighting romans

1 ) I wiped out green and blue romans. on my way to rome, and red ones now.
2 ) I learned to make my hoplite out of phalanx mode than back.
3 ) I am using them close on flanks so nobody gets between, they only fight in front.
4 ) I started to use archers.

I checked the unit guide, It says cretan archers and rhodian slingers. Can I make them or are they mercenaries limited to certain areas ? Also can I make spartan hoplites in every city or only in certain cities ?

thanks for all your help. Greeks are really fun to play with. I am fighting with selucids and pontus on the east, red romans and carthage on the west now. ( campaign and battle difficulty : hard )