This would also be interesting. If I understand you right the Kongolese would have access to cavalry but also to that “Pombo”? That would allow for a very unique unit design probably. As you wouldn’t need to have a unit that can perform the same utility as the cav in the mid and lategame.
I actually was inspired by the proposal for the Mississippians . So you’re right it doesn’t really fit in south america.
But I don’t want to change the Incas either. The idea was to give it to new south american civs that at some point also get access to light cav, as the conquistadores brough horses and some of the cultures there reportedly started breedy their own horses quite shortly after that.
This was intended to give a good distinction between the mesos and the newer south american civs, which at least would have these light cav to deal with monks in the midgame. And ofc to have light cav as trash units available in the lategame aswell.
This also frees up some more creative space for the foot scout line as it wouldn’t be required to counter monks, so it can be stronger against other units, like Cavalry.