yin chakra will make him weaker,since his bijuu mode will become like bee,where he can get hurt when his bijuu gets hurt,current BM is better.
other tailed beast chakra will play a role in defeating the juubi only:i believe somehow using that chakra he will split the juubi back into bijuus once it reaches the final stage,then that chakra will dissapear.
SM+BM:really hard to obtain,since he needs to balance all of kurama's chakra(which is a lot)with an enourmous amount of natural energy,that means he will have to stay still for a lots of time,which is not really practical for battle.