Again, where or how can I know about the current state of local happiness and unhapiness? How do I know about a particular city's happiness and unhappiness?
AFAIK, until someone creates a mod to display city LH output in the city screen there is no good way to handle it.
For now the best way is to go to the economic overview window/Resource & Happiness tab, then expand the Local City Building list to display each cities LH production then compare to city pop.
I am still sorting out what sources are what but so far:
All standard H buildings are Local including stone works.
NW:
Local: Circus Max.
WW:
Local: Chichen Itza, Tah. Mah, Neusch. Castle +2H in city
Global: Eiffel Tower both +5H and 1H/2Pol, Neusch. Castle +1H/Castle (all cities)
Forb. Palace effects Unhappiness so doesn't apply.
Policies:
Global: Aristocracy (Doesn't count for occupied cities including puppets)
Local: Military Caste, Prof. Army, Humanism
Monarchy effects Unhappiness so doesn't apply.
Local Luxury Res, Traded Lux Res, City State, Natural Wonders:
All Global
Religion:
I recall that the next patch will define Founder beliefs as global and Follower beliefs as local. I can't recall what they said about Pantheon but I'm guessing global.
Unfortunately this implies it's changing from something else currently. I do know that the religious buildings I've checked so far are local and assume it's consistent.