You can store up to 1000 contacts in Metro XL. In addition, you can store up to 250 contacts in each of your sim card. So, if you are using 2 sim cards, in total you can store up to 1500 contacts.
No. This phone do not have wireless FM.
Yes, you will get a pair of headphones in the box as standard accessories.
Yes, you can do that.
No. Samsung Metro XL does not support Nimbuzz chat messenger.