only with cheats or by trading
yes but only by trade
No, you won't be able to acquire a Sinnoh Starter in Pokémon HeartGold and SoulSilver, you'll have to trade for any of the Sinnoh Starters.
you can't get sinnoh in heartgold.
its impossible to get sinnoh starters without trading them from other gen IV games. use the palpark in fuschia city to trade them from pearl/diamond/platinum.
Pokemon HeartGold Will Have Sinnoh,Kanto,But Hoenn Least Likely.
only if you trade from pearl/diamond/platinum
You cannot do anything in Sinnoh in HeartGold. You can only go to Johto and Kanto. Sinnoh is not available to travel to.
no
you simply cannot
Duskull is a Sinnoh pokemon as in pokemon platinum you get darkrai which is the evolution of duskull.
If you have a friend who owns Platinum, Diamond, or Pearl ask to trade with them.
You don't you have to migrate to get sinnoh pokemon.