You can get Hatena characters either visiting a cardass machine in Japan, and spending 100 Yen, or using binary's EnTama cheat
here.
In the ABCD digit thing insert:
5185 for dating card number 1
5186 for dating card number 2
5187 for dating card number 3
Nº 1: Hatenatchi > Meganetchi > Ohigetchi > Nekutaitchi
(Unknown > Glasses > Moustache > Necktie)
Nº2: Hatenatchi > Getatchi > Rakugotchi > Kabukitchi
(Unknown > Sandal > Thing-on-a-pillow > Mask)
Nº3: Hatenatchi > Okutchi > Shiripuritchi > Ashitchi
(Unknown > Mouth > Bum > Foot)
This should tell you everything, and if you are interested in directly viewing them in e-tamago, please visit
this topic here which has quite a lot of passwords.