Yes, It Can, But I Say You Should Get The Accum One.
Although the Ava's accumulator/attractor can retrive 45-75% of your arrows and attract metal it does not, because you deposit 30 in the cannon, and it never adds to the inventory of cannon balls.
Yes.
Yes, it attracs all ammunition other then from the cannons.
its very simple... finish the quest Animal magnetism and you get a attractor in reward... bring like 1k stee arrows or something with it and a k gp to the witch and she will make it a accomulator... IF you got a ranged lvl of 50
Sadly no, it seems to only attract steel objects - however if you were to fire any type of arrows (except the god arrows from clue scrolls) there is a chance they will get picked back up - provided there is no object in the way of your firing range (fence, slope or wall etc.).
If by "backpack" you mean "Ava's Attractor", this can be obtained by completing the Animal Magnetism quest.
Ava's attractor and accumulator add range attack bonus, and it is worn in the cape spot. It is obtained through the quest Animal magnetism.
Ava
Ava Telek goes by Ava Maria.
Ava Shamban goes by Dr. Ava Shamban.
Ava Sambora's birth name is Ava Elizabeth Sambora.
Ava June's birth name is Ava June Wiggins.