^^ something I've noticed playing the Venice a bit; is the Tradition opener doesn't work on the puppeted citystates. And the addition of the aqueducts and monuments is sometimes hit and miss... Anyway; I''m thinking a Piety venice start would be worthwhile too; get Tithe and spread it about for fun and game.
Venice has the same rule as Austria. (And other extremely early war monglers):
For legalism: Cities you already have at the point you get Legalism count. (Up to 4). But if you don't yet have 4 cities, you have to build a new city to get the Monument and capturing / marrying / buying will not work.
Tradition closer: Again: Cities you already have at the point you close Tradition count and get Aqueducts. But if you don't yet have 4 cities, you have to build a new city to get the aqueduct and capturing / marrying / buying will not work.
On the tradition opener: As far as city expansion goes, it's being offset by the 25% culture expansion penalty all puppets has; and it appears to truncate the culture you got down to the nearest number. (If there is a Gold resource being worked and you have religious idols, that 1 culture upon getting the 25% reduction goes away entirely.)