Yes, Metro 350 does have FM Radio.
Yes, you can use up to 16GB external memory card with this phone.
Samsung Metro 350 has 1000 contact storage capacity.
Yes, Metro 350 does support Gujarati language.
Samsung Metro 350 has quite good battery backup. It comes with 1200 mAh removable battery and on a single charge it can last up to almost almost 4 days.