1. How does AC from a gear "special properties" (e.g. shaman robe) figure into this? Is it just the intrinsic AC that counts, or both?


Nope. Only the AC vs. a specific attack type counts towards deflection. Generic AC does what it did previously.

2. What about AC from songs/skills/spells/communes (e.g. armor spell)?

The more powerful affects can bolster existing armor AC. If you have one up you'll notice rare deflections credited to them.

3. The new "magic" damage category for base AC: does it cover stuff like light, black light, wrath/divine, defilement/unholy, poisonous bite, etc.?

Anything not covered by a physical damage type or one of the elements. Radiance is a (quasi-)element, the rest fall under magic.

valguarnera@carrionfields.com