1 - yes, only 2 factions only in Italy
2 - no, Venice and Milan have the unique buildings, the rest is for all provinces, even if the description is from Genoa and the pic from Florence
3 - no, from the beginning till level 4, then after Dante is born - the other levels
4 - yes, no connection with the Italian Traders
5 - yes, but my modding is not so planned, I've just spotted a good Palazzo building to make pics out of it.