My answer is based on actual experience: I put a (female)roselia and (male)shroomish in the daycare on ruby, and they had an egg (it hatched as a roselia). However, I put a (female)pikachu and (male)minun in the daycare on emerald, and they didn't have an egg. Hope this helps a little. Sorry for not having a direct answer ;)
No, it doesnt. Pokemon are put in "breeding groups" and only Pokemon in the same group can breed.Such as if Jynx and Sneasel are in the same group, they can breed, just as long as they arent the same gender :P and they have to have genders, Pokemon such as claydol with no nature cant breed.
Yes, as long as they are in the same egg group. It is even possible to breed Wailord and Skitty.
Pokemon in the same egg-group as gardevoir
Male and female pokemon in the same egg group can make eggs. Also, any pokemon that can breed can breed with a ditto.
Egg groups indicate which Pokemon can breed with which. One Pokemon can be in several different egg groups, and some are in no egg groups at all because they cannot breed (legendary Pokemon, for example). If you want to breed your Pokemon, first look up what egg group(s) it is in, and then what other Pokemon are in the same group(s).
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, they are not in the same egg group.
On Island four there is a daycare and you have to put ina male and female Pokemon of the same egg group, or breed any Pokemon with ditto
Breed your piplup with a ditto. Or breed a femle piplup with another Pokemon from the same egg group as piplup.
No, you do not. You need a male and a female pokemon within the same egg group, or ditto and a pokemon or two dittos
Most of the time, yes. Breeding compatibility is controlled by egg groups. If two pokemon are in the same egg group, they are compatible to breed. Many fire type pokemon belong to the same egg group as other fire pokemon, but not all.
no as long they are the opposite gender or any gender can breed with with a ditto