Yes, Samsung Guru Music 2 works with Kannada langauge.
No. FM Radio recording is not possible.
This seems to be some software related issue. You should visit the nearest Samsung authorized service center and get it checked.
No. This phone do not have call recording facility.
Samsung B310 comes with 800 mAh battery. But it is very efficient. You do not require to charge the phone for almost 3 days with moderate usage.