No. Call recording option is not available in Samsung Guru Music 2.
Yes, you can use 3.5 mm headphones in this mobile phone.
Samsung Guru Music 2 can store up to 500 sms.
Yes, you can create contacts groups in Samsung Guru Music 2.
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.