They recently changed the rules so friendly fire isn't an automatic crime. NPC's on your side will take a little accidental damage before they retaliate. Certain variables like what weapon you used, your status with their faction and the condition of their shields are taken into account. So if your friendly or allied they will be more tolerant.
I don't think bounty sharing is a thing yet, not until 1.2 wings on tuesday. Then rewards are shared between other members. I don't think it matters whether its trading, bounties etc. Not sure how it is divided though.