Fill up the rest of your Pokedex!
There isn't a difference in wild or legendarys. The only difference is that the main legendarys are switched but your able to get them anyways.
you get all the kanto starters, hoenn starters, all legendarys and that what happens. (legendarys are, ho-oh ,lugia, latios, latias, entai, suqcoon,raiko,articno,moltres,zaptos,mewtwo,kyogre,grouden,and racqaza.)
evey Pokemon has an egg except legendarys and ditto
enti, raioko, suicune, lugia, ho-oh, articuno, zapdos, moltres, mewtwo, mew (event only), groudon, rayquaza, kyogre(heartgold), celebi (event only), latios, latias(heartgold or event).
Zapdos,Articuno,Moltres,Rayquaza,Kyogre, Groudon,Mewtwo,HO-OH, Lugia, Raikou, Entei, Suicune, (Celebi and Jirachi are event pokemon)
go to serebii.net and look on the left for hggs pokedex and go to the Pokemon you want to catch and it will tell you everything about it
you have to have all the legendarys
get all the legendarys
All of them, if you trade with other games.
No. There was a special Arceus event that could be used to get an Arceus , but if you didnt do that, you must get an action replay, or get the the azure flute via mystery gift for Diamond, Pearl, or Platinum. Bear in mind that if you did not do the special 12th movie Arceus event, you can only get one of the Dialga, Palkia, or Garatina that comes out of this event. But also keep in mind you dont have to catch all the legendarys in heart gold to do this event.
you keep playing...
all over the place. look for them