Tune your radio to the Pokemon music channel on wednesdays and search through the grass with the Hoenn music, and you may find one.
You can't find a Whismer walking around.
you need to breed loudred it can be found on mount corenet with pokeradar
You can't catch Rotom in heartgold.
you cant catch him in heartgold you can only get him in soulsilver
In HeartGold you can catch Kyogre.
You can only catch Vulpix in SoulSilver, not in HeartGold. You can catch it on route 36 and route 37.
In pokemon Heartgold
No
you cant catch it it is rare
You can catch Lombre in Pokemon HeartGold in the Safari Zone at a waterside area once you receive the National Pokedex.
yes you can catch every Pokemon ever made
You can catch Ekans in Pokémon HeartGold in the Safari Zone in the Marshlands area.