We got a lot of new information from the Civ7 November live stream!
Spain got revealed as an exploration age civ. Spain is an expansionist and militaristic civ with a coastal starting bias. They got boni if they convert towns to cities in distant lands, incread combat strengths in distant lands, and they get a special conquistador UU, which all have unique abilities. For more info please check the thread. We got no thread for the new civ Mexico though, as we only got a glimpse on the name in the live stream.
Spain though will most of the time probably be lead by Isabella. She is economic and expansionist, and dislikes players with a lot of natural wonders. She gets a starting bias towards natural wonders, and her special ability will give her more gold from natural wonders. For more info please see the thread here.
We also got new information on religion, which is a mechanic from the exploration age. There are 12 religions in total, which can be customized with different beliefs. They get temples as buildings, which are necessary to build missionaries. For more info please check here.
For the exploration/military side, we also got interesting news. While commanders are land units which allow you to easier organize your army, we also get fleet commanders at sea. They seem to be working like normal commanders, getting customizable boni, and Spain gets some specific unique units which give them boni. For more information please check here.