No, there are no underwater routes in Pokemon HeartGold or SoulSilver. The HM Dive is not available in Pokemon HeartGold or SoulSilver.
Well, I know Dragonite can know it. Some Legendaries can learn it, like Mew. I know it's mostly Dragon types you see that use Draco Meteor. In Platinum, if you tag battle with Riley, he'll have a Legendary or Pokemon of some sort that knows Draco Meteor.
you cant catch persian in heartgold.... i think
YES=)
Yes you most definitely can
Kyogre is in Pokemon games emerald gen.3, ruby gen.3, sapphire gen.3, firered gen.3, leafgreen gen.3, diamond and pearl gen.4, platinum gen.4, heartgold gen.4, soulsilver gen.4, black gen.5, wight gen.5, black 2 gen.5, wight 2 gen.5,
Depends. Biggest as in heaviest is Groudon, 3rd gen. Tallest is Rayquaza, also 3rd gen.
It is regrettably not possible because Pokemon white is gen 6 and heart gold is gen 5 therefor rendering them incompatible
I doubt there will be another one. HeartGold and SoulSilver are part of the generation IV pokemon games, and right now the most recent gen is generation V
You cannot in HeartGold or SoulSilver. However you can do this in the Gen V games.
Ilex Forest in not in Firered. Ilex Forest is located in Johto. It can only be reached in Gen II or in the unreleased Heartgold and SOulsilver in Gen. IV.
2 magnemite and a steelix
You have to trade it over from a 4th gen game (Diamond/Pearl/Platinum) or from a friend. You can't get a Prinplup otherwise.
You get kyogre by trading or migrating it from platinum, diamond, peral, or heartgold, and the gen 3 games sapphire and emerald
There are not ANY AR codes to get 5th gen Pokemon in Heart golds/Soul Silver. ARs only unlock stuff that is already programmed into the games. 5th gen Pokemon are not programmed into those games, only 4th gen. Only way to get 5th gen Pokemon in earlier games is to hack, but I stronly advise you, and anybody really, not to do that because it can destroy your game. Just get Pokemon B/W and you get the 5th gen Pokemon.
If your asking if you can catch them, yes. Shiny Pokemon were introduced in Gen 2, FireRed is a Gen 3 game.
There is no best Pokemon on Pokemon HeartGold.