Latias will first start appearing in the wild after Steven Stone talks to you in Vermillion City. She always escapes at the start of battle, and she has a rather high Speed stat. Because of this, you might want to equip a Pokemon with the Quick Claw and have it use Mean Look.
Her ability: Levitate (immune to Ground type moves)
Her moves:
Dragon Breath
Water Sport
Refresh
Mist Ball
Mist Ball is a Psychic type move, her main move, her most powerful move, and due to a high Special Attack, can be dangerous.
A Good Catching Strategy:
Have a Pokemon such as Umbreon, Honchkrow, Crobat, or Jynx learn Mean Look. Equip it with the Quick Claw. Once you encounter Latias, you should use Mean Look and switch right on to a Sneasel or Weavile. You would want these Pokemon because they are Dark types and are immune to her Mist Ball move.
Also, they can learn False Swipe, which, even if that move was supposed to be a KO move, will leave the opponent with one HP.
Do NOT use your Master Ball here. It is not worth it. An Ultra Ball should work nicely here.
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.
No
In pokemon Heartgold
you cant catch it it is rare
yes you can catch every Pokemon ever made
You can catch Lombre in Pokemon HeartGold in the Safari Zone at a waterside area once you receive the National Pokedex.
You can catch Ekans in Pokémon HeartGold in the Safari Zone in the Marshlands area.
there is no Pokemon called croagoak
yes