You can only transfer the Manaphy egg. Get the Manaphy egg code and then link the games up wirelessly and transfer it. Then go to any poke mart and talk to the green man with the hat on. He will give you the egg that you sent over.
Jirachi cannot be caught in Pokemon Diamond. It can, however, be transferred from Ruby, Sapphire, or Emerald, assuming you got it from a Nintendo event.
Misdreavus cannot be caught in Pokemon Diamond. It can be caught on Pokemon Pearl appearing in Eterna Forest and Lost Tower at nighttime.
Magikarp
Slowpoke cannot be caught in Pokemon Diamond. This Pokemon can be found on route 205 in Pokemon Pearl using the pokemon radar and traded to Diamond.
Oshawott can't be caught in Diamond.
noctowl and hoothoot
Questions like this are always asked. You can't catch this Pokemon in diamond or pearl versions of the game, only in the older fire red and leaf green versions. They can however be transferred to Diamond or Pearl once caught by going to Pal Parkafter you beat the Pokemon league.
Cresselia
You have to have seen or caught every Pokemon in the game
no sorry it can only be caught in diamond
You would need a special connecting cable, but I'm not sure that they sell them anymore. I think that they stopped selling them about a year ago... BUT!! if you have the pal park in Pokemon diamond (after you get the national pokedex you get it) and you place your GBA Pokemon game in your ds (such as Pokemon ruby...) and your Pokemon diamond in your ds and you PLAY your GBA version, then all recently caught Pokemon from your GBA game will be automatically transferred onto your ds version in the pal park. After the transfer, if you enter the pal park you will find your caught Pokemon and you can re catch them but on your ds version!! HOPE THAT HELPED!!!
Unfortunately, you cannot nickname traded Pokemon in this game, or any Pokemon game for that matter. You can nickname your own caught Pokemon by going to the Condominiums next to the PokeMart in Eterna City and ask the old man near the entrance. I hope that you will make do!