FRS XP should only be awarded for opposing enclave kills, and the xp should not be split like it is in vanilla. If you allow it to be awarded on non Jedi kills (like BH) it is far more open to exploitation and fight clubbing.
In regards to the credit sink issue - In my opinion the best solution would be that the bounty hunter has to pay a fee to accept a mission that is a % of the payout itself. Upon completing their mission, they receive that money back, or upon failure, that money goes towards the person being hunted. So there is some incentive to stay in fight.