Question

For happiny, bonsly, and magby.

Answer 1

http://www.serebii.net/diamondpearl/breed.shtml

Make a Female Sudowoodo hold a Rock Incense to get a Bonsly Egg
Make a Chansey hold a Luck Incense to get a Happiny Egg

Magby does not require an Incense to obtain via Egg. To get Magby via Egg, breed a Magmar with a Ditto to easily get a Magby Egg.