Not all units add attack to buildings. That's settable per building. But normally, every ranged unit and every infantry unit adds arrows to the building. So a ballista in a fortress adds arrows (it's ranged), a swordsman adds arrows to a fortress (it's infantry). The main category that isn't included are the melee cavalry units.
The most notable exception to this general rule are the quinqueremes. There only ballistas add arrows (or rocks) to the fire rate.
The number of arrows per unit added can also differ per building. Like in the defense tower, you have a tech that adds 1.4 arrows instead of 1 arrow per garrisoned soldier there (if I remember the numbers correctly).
The range, and the strength of one arrow is fixed per building.
Having all this info inside one tooltip (classes that count, number of arrows they add, ...) used too much space. So we opted to just show the rate after garrisonning.
The auras indeed are mostly working. Except those of the new civs (Ptolemies and Seleucids) might be missing in our latest release (and might have quite un-specific tooltips). And they're not very powerful as I just implemented them as examples. Hoping some balancer would come by and make them interesting enough to use, but not overpowered. I prefer underpowered auras over overpowered stuff. As they're very civ-specific, and overpowered auras would just give a big advantage to one civ, and make the entire game unbalanced. When they're underpowered, they're just not used.
We're also looking into a way to visualise the range auras. There's an example visualisation for the Athen temple, but it requires GLSL to be seen.