Hello!
1) looks like the "Ranged Weapon Strikes" text is under Batched Arrow but yes, I do believe that is a typo. I may have intended the Batched Arrows to be good for any ability... I think if it was only 1 extra damage that would be ok. I will add this to the errata until I can official update it! Which *should* be before the end of the year. I have an update push planned for all of these products in anticipation of me finally getting around to finishing the next installment "Essential Apparels!"
1.5) That did make me realize there *is* still a typo in Banger Arrows referring to them as "Blinding Bangers", an item from Alchemical Consumables. Also in errata.
2) The design in mind was to have them fit neatly beside other consumable items that allow you to make a free strike as a maneuver + cool effect (such as black ash dart). Restricting the arrows to be used only on free strikes and not allowing them to be their own maneuver free strike allowed them to be a little beefier, have a higher crafting yield, and in some cases forego a potency check on added effects. Regarding use on regularly abilities, the intention is that they improve your free strikes into something cool *instead of* piling onto the other cool things you can already do. Making regular abilities "too strong" is a conclusion I came to, but it is more about uplifting free strikes to something closer to a custom situational signature ability than balancing them out of use in regular abilities. But the included "Trick Archer" Kit lets you use them on it's Kit Signature! So there is that option.