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.
No. Call recording option is not available in Samsung Guru Music 2.
Samsung Guru Music 2 can store up to 500 sms.
This seems to be some software related issue. You should visit the nearest Samsung authorized service center and get it checked.
Yes, but you have to use sim card adapters to make them work.