nothing search for latios/latias
You cannot get a Sinnoh Starter. You can only have a Kanto, Johto, and Hoenn starter.
No you do not need to catch Kyogre. You can get a Hoenn starter from a guy named Steven in Kanto.
Silph.Co(Kanto, postgame)
No, you do not get to choose a Starter Pokémon in "Pokémon HeartGold" immediately after arriving in the Kanto region however later on after you've defeated all of the 8 Kanto Gym Leaders including Blue, you'll get to choose a Kanto Starter and a Hoenn Starter.
In Pokemon Heartgold and Soulsilver you can get a Johto starter from Professor Elm, a Hoenn starter from Steven, and a Kanto starter from Professor Oak
you catch the hoenn legnds kygore groudon and rayqaza
Hoenn is not in heartgold version, only johto and kanto are in heartgold, hoenn is in emerald
You can't get to the Hoenn region in HeartGold or SoulSilver. However, Latias can be caught in HeartGold, which is a legendary from Hoenn.
In Pokemon Emerald, when you complete the Hoenn Pokedex, Proffesor Birch gives you a Johto starter. In Pokemon HeartGold and SoulSilver, after defeating Red, Professor Oak will give you a Kanto Starter and Steven will give you a Hoenn Starter.
Getting the Hoenn Pokemon is completely optional. Therefore, there is no chronological event that is placed after getting your choice of Hoenn starter. Just try doing some other extra events.
once you defeat red in mt. silver he will give you a kanto starter.... After that you should go to saffron city in the silph co building and he will give a hoenn starter on the colour stone you choose.
After defeating Red at Mt. Silver, Steven Stone will be at the Silph. Co and he will give you one there.