Re:Which is the best combination of buildings?
Aqueduct and small market are very different from each other. Aqueduct is interesting in that its not an 'auto-build on turn 1' like small market is. It makes lagre indigo and sugar mills decent. But I kindof like small market in the game too.
I personally think that Black market really screws up the game, and in fact, it is WAY more beneficial to corn positions than indigo, and corn positions didnt need more help. It makes player 3 even better than before. I'd stick to haci and con hut.
I think small warehouse is better to have than storehouse. There are other buildings (factory, harbor) that already favor diverse goods. Small warehouse favors specialization, I think that should be a valid part of the game (its already weaker, dont weaken it more).
Guesthouse is much better than hospice, as is trading post much better than office. Church is pretty broken, imo, and I would go with large market and trading post. (Possible with the modification to trading post that if the trading house is unempty, and you use it, a good still goes on the house. That way you cant lock the house for people without trading post, yet trade yourself).
Small wharf is a much better choice to have than large warehouse. Its very balanced and adds to the game.
Factory is much more balanced than lighthouse. I love lighthouse, but its a bit broken. It would be better at 8, replacing the university. Neither of the new 8 cost builsings are any good, but at least library is significantly better than university. I'd put in whichever of library or spec. factory someone in your group would actually use.
Wharf is far more balanced than union hall. UHall is broken.
I'd go with all the basic larges.