>Will there be unique content for Spanish colonial activities like the repartimiento, the encomienda, and cabildos?

Yes, a lot. For instance, this is an event about the Leyes of Burgos, and what it unlocks:

Note: the event is showing European slave pops because I triggered it through console; if triggered organically, then the enslaved pops that would correctly be shown would be of the Native American (Aztec) graphical culture.