Yeah you are right on the Iroquois being anachronistic
However, the Mapuche symbol isnt from the flag, its a religiouw symbol Meli Witran Mapu - Wikipedia, la enciclopedia libre. I wasnt able to find when was in created, but its prob older than that. Other option is the Lautaro banner which is on period.
The maceman could very well be Chimu’s unique unit. Despite mace being a relatively common weapon in medieval era across the world, we still don’t have any unit in the game that uses it.
And we also don’t have any unit that uses the trident. I think if the Dians or the Siamese get introduced into the game then there could be a trident warrior unique unit (or regional unit), since from what I know the trident was a rather common weapon in medieval Southern China and SE Asia.
Indeed, many native peoples used some type of symbol to identify themselves. Even the facial paints serve to differentiate one tribe from another.
There are also cases where native peoples take a defined emblem and represent it on their shields, for example the Jivaros used that symbol since colonial times.
I would also like to see more maces in AoE 2, it was a very common weapon in the middle ages (although many people associate it with backward or archaic technology).
I’ll also admit that I’ve been heavily influenced by the term “Hammer of Justice” thanks to Blizzard’s Paladins
In this pectoral, six birds with folded wings and crouching human figures on their heads, rest on the back of a larger bird. Another two human figures, also in a squatting position, sit on its open wings.