I would reiterate that the happiness is province wide but the food is factionwide
I am currently trying to juggle this with Sparta 50 turns in

Apolonnia has inf rax/ skirm rax and 2 workshop upgrades - pretty much everything else is trying to keep people happy enough
Pulpelona (Spelling?? is making food - lots of food wherever possible
Athens is making sanitation and city center stuff mainly with trade and cashola on the side - struggling to grow now but on reflection that may be because its already maxed

I would very much like to see how people are splitting their specialisations and keeping enough happy citizens - having a military sector is obvious but the rest is beyond me at the moment