It seems strange that the only limitation on Improved Bow Construction is "cannot be used on firearms". Is this trait intended to work with thrown weapons and heavy military weapons?
Also, for the purpose of applying Advanced traits do you pick the weapon and modifier when you take the trait or can you mix and match when you're selecting gear during roster design? For example, when I pick "Improved Bow Construction" would I need to specify, "only on longbows, only for +1 ranged" or could I apply it generally and use it if the unit take longbows, recurve bows, sometimes for a +1 to hit or other times for an increase in range?
Here's the source of the confusion: Under Heavy Military Weapons, Tier 2, the trait "Advance Military Weapons" seems to give you the ability to add Ranged Traits to Heavy Military Weapons. I'm guessing that needs to be fixed to Advanced Heavy Military Weapons 1 (with the disclaimer removed).
Yes, that makes sense.
As for the 0 point traits, I read somewhere on the forums it was going to be errata'ed to be require a mission reward to take a 0 point trait.
'No' to both, although there is a case for Thrown Weapons to be added in via errata.
If you look on page 122, Advanced Ranged Weapons "Includes all ranged weapons such as Crossbows, Bows, Firearms, and Repeater Crossbows." Improved Bow Construction is giving you the Advanced Ranged Weapons 1 ability, with the exception that it cannot be applied to firearms.
Heavy Military Weapons are radically different and accordingly are both categorized differently and have dedicated traits for their improvement.
Picking the attributes/weapons to be upgraded is done when creating your roster for a game. The Advanced Ranged Weapons ability says that it's the adding of extra attributes that costs points, so the Trait itself is actually free. While this runs afoul of the errata that prevents 0 point Traits from being taken at Faction creation, it wouldn't be a bad idea to grab it the first chance you get.