Enter the following codes in your personal message of your friend card, and you'll receive a message 'password accepted' along with the corresponing item:
Player Icon: Chocobo (FF5) 582052436
Player Icon: Moogle (FF5) 134103103
Capricorn Recipe: 870322642
Aquarius Recipe: 3927540667
Pisces Recipe: 531062973
Friend Card: Matoya 3939258263
Friend Card: FuSoYa 29432971
Friend Card: Siegfried 20151231
Friend Card: Vivi 3784227940
Friend Card: Auron 1298228499
The recipes are especially important. From BradyGames Guide:
"Password recipe: Accessories with this appearance condition do not appear in the shop until you enter a special password in the personal message section of your friend card. The developers plan to reveal these passwords in the weeks and months following the game's release."
There apparently are going to be more passwords released, so keep an eye out and post them here if you find them.
