Adding the fish from the inlaws is okay and is best if they are eating pellets. Thus you get pellet trained fish. Adding BG is not real productive unless you are removing numerous bass (lions) from the 'barnyard'. The clear water means the lower end of the food chain (plankton & invertebrates) is low and will not support a lot more panfish than what you have unless productivity or pellets are increased. Reducing predators will help in reducing the predation pressure on the panfish. But without improving the food sources (food chain) additional panfish will be slow growing and thin bodied.
Lots of homework for you to do.
Read and study about carrying capacity.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=92440#Post92440Learn about fish population analysis.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=92492#Post92492 
