Some observations on re-viewing the demo:
1. When he showed particular wonders and buildings that had slots for Great Works and Artifacts, there were no specialist slots for Amphitheater, Opera House or Museum -- just Great Works/Artifacts slots. (Same city had a market and workshop, with traditional specialist slots filled.) Unanswered questions: If there are no artist slots in culture buildings, how will you generate Great Artists, Writers and Musicians? Will you produce them like other units? If so, what techs will unlock particular types of Great Persons?
2. Palace appears to come with one Great Works/Artifacts slot, Louvre had 4, Amphitheater 1 (Literature), Opera House 1 (Music) and Museum 2 (Art). In the Renaissance Era, each Great Work generated 2 Tourism and 2 Culture. The Tourism tooltip also said there was a 25% Bonus for Open Borders with France, which showed up in the Tourism overview screen (Brazil and Assyria were experiencing 18 Tourism, while France was at 22 (extra 4.5, rounded down)).
3. River tiles had no gold yields, as previously reported. But his cities all showed the regular trade route symbol (black triangle with 3 yellow dots), so old fashioned trade routes appear to still be enabled.
4. 2x gold multiplier for sea trade route vs land route.