Noble is the closest difficulty to being equal but the players advantages of specialization, war and micromanagement can still easily overwhelm the dumb AI on Noble.
In no particular order as these 4 are all great.
output on their own and some have benefits that will prove very useful for culture wins (sistine in particular).
will get you the techs you need sooner and can then be converted into .
savings on the load of temples your going to want as well as civic swapping, building structures is going to be important here so OR is great and lets you build missionaries without monasteries, slavery is always handy and your going to need a GA farming strategy so Caste and Pacifism are very, very useful. Plus Spiritual can help you stay alive.
I was told long ago that they start entering your borders when the number of cities on the land mass = n*2, where n is the number of civs on the landmass. So, more or less, when everyone has a second city. But if, say, you share the continent with Brennus and Gandhi, and you have 1 city, Brennus has 2, and Gandhi has 3 (3*2=6), the barbs will start coming by to party. In other words, you can't hold off the barb invasions by waiting to found your 2nd city, especially since the AI loves to REX. .
Creative isn't very good despite appearances, I think its very unlikely to account for even 2% of the total culture you actually need
from Creative doesn't itself help a whole lot in this respect. However, Creative also gives you cheaper Libraries and Theaters. Theatres in particular are useful because they allow you to run artists and increase the impact of the culture slider on your happy cap. 
