I have a small question about the Antesignani. In everything I've read there is no mention of "Light Infantry" within the Legions themselves. From everything I've read the "Light" Infantry was provided by Auxiliary units. They were often trained to be better than the Legionnaires themselves in combat for the express purpose of ambushes. scouting, and their lack of heavy armor.
I was also curious why they were armed with a spear. The Legions never had spears, and only certain Auxiliaries would use spears, since the offensive nature of the Legions of Rome meant that they were better served by swords, as they always moved into meele as quickly as possible. I would think that as a scout/ambush unit the Antesignani would use swords, since they would close a.s.a.p.
In fact, the only times that I've read of Legionnaires serving as "Light" Infantry was during the late Imperial period. Though the truth is that they did not serve as regular Light Infantry. They would, to react to Germanic and Getic raids, take off most of their heavy armor and only use a "heart" breast-plate (like the one the Polybian Hastati wear in-game). After this they would invade the tribe and take all of the material wealth and slaves they could, to make a show of Roman invincibility.

My question is, why are Antesignani a "factional unit"? Wouldn't it be more accurate to place them within Regional MICs? Also, why are they in the Marian Period only, if they only really came into their own during the Principate?