No. It's always gonna be Cleffa. In other games maybe, but not in Diamond or Pearl or any region ahead of Sinnoh.
Clefairy's Egg Group is Fairy, so any Pokemon with the same Egg Group can breed with Clefairy, including Ditto, which has its own Egg Group.
no
No.
You can catch it at Mt. Coronet.
you can get a clefable by giving a moonstone, found underground in diamond and pearl, to clefairy
moon stone will help
in caves and mountains, especially mt. coronet
The Pokemon clifairy does not exist. Clefairy is found in mt. coronet.
Clefairy is the only Pokemon in pearl that evolves with a moon stone but once you get the national dex you can evolve Jigglypuff, Nidorino, Nidorina & Skitty
their is no darkri egg, you need the event
Nidorina Nidorino Clefairy Jigglypuff Munna Skitty
The mysterious egg is an item in Pokemon Pearl version. It will hatch into either a Happiny or a Riolu.