The overall picture on the diplo front is that:
- Freedom lets you gain votes and city-state alliances with almost no demands on your economy and production, and with little care about geographic constraints. It favors civilizations focused on trade, espionage and great people generation.
- Order has no tenets focused on city-states and the World Congress.
- Autocracy directs its military production and deployment to secure city-state alliances and extract more benefits from such alliances. It naturally favors militaristic civilizations.
Freedom's Treaty Organization (tier 3 tenet) scales with the original number of city-states; in a standard map size, the tenet gives 8 votes immediately. The other part of the tenet is a doubled version of Statecraft's Trade Confederacy, letting you have up to +10 influence per turn on each city-state you have a trade route with, which makes Freedom a solid diplo choice for trade-based civs, like Carthage and Venice. Freedom also has two extra trade routes with Economic Union (tier 1 tenet) that lets you get more from Treaty Organization.
The other two diplo tenets on Freedom are Covert Action (tier 1 tenet) and Arsenal of Democracy (tier 2 tenet). The former makes your spies highly likely to succeed on coup attempts, often at 60% - 80% - 100%. It also gives you extra spies based on the number of original city-states. The latter gives you some diplo to every city-state upon spending a great person.
Order has no tenet that directly affects city-states and the World Congress. At best, you use Order's production and infrastructure to spam as many diplomats as possible.
Autocracy's United Front (tier 1 tenet) boosts the influence from gifting units to 40, halt influence decay during wars and triples the frequency that militaristic CS gift you units. Tyranny (tier 3 tenet) lets you demand tributes from friendly city-states to gain what is essentially a great diplomat effect on them. Iron Fist (tier 1 tenet) increases yields from friendly city-states by 25% and ensures your vassals can't rebel or be liberated.
Note that there are three national wonders that require a specific ideology and grant votes based on your diplomacy with other major civs. Freedom's one grants votes from declarations of friendship, Order's one grants votes from defensive pacts and Autocracy's one grants votes from conquered capitals.
On the happiness front:
- Freedom has plenty of happiness sources and is the most resilient against boredom. Reasonably resilient against distress and poverty as well due to its boosts to food and golden ages.
- Order has good amounts of yields, especially production, leading to addressing city needs in a relatively balanced manner.
- Autocracy has less city yields than other ideologies, but has plenty of happiness from conquests and modifier against distress.
Freedom has direct happiness sources on every city from Universal Suffrage (tier 2 tenet), Capitalism (tier 2 tenet) and Media Culture (tier 3 tenet), with Capitalism being particularly strong due to also reducing urbanization by 2 in every city and turning it into 2 happiness instead. Freedom also has plenty of food from Urbanization (tier 1 tenet), culture from Creative Expression (tier 1 tenet) and Media Culture (tier 3 tenet) and gold from Capitalism and Economic Union (tier 1 tenet). Freedom also has frequent golden ages due to Universal Suffrage and Creative Expression, which do wonders to address non-illiteracy needs. The main weakness is addressing illiteracy.
Order has plenty of production, free buildings and has need reduction modifiers for non-boredom needs. It also gets happiness in every city with People's Army (tier 1 tenet) and Dictatorship of the Proletariat (tier 2 tenet). Heavily focused on food, production and science, it's main weakness is boredom, followed by poverty, as the ideology is relatively light on culture and gold generation.
Autocracy has the lowest amount of city yields and only has need reduction modifier to distress. It's main source of happiness comes from Police State (tier 2 tenet), which gives +3

happiness on courthouses. Expect it to suffer from city needs the most, but get a major happiness source on tier 2 if you conquered a large number of cities.
Note that there are three world wonders that require a specific ideology, and they can further help with happiness. Freedom's wonder gives +1 production on every specialist, Order's one negates tourism tech modifiers from other civilizations (less issues with dissidents) and Autocracy's one gives +1

happiness for every 2 policies you unlocked.