He is on route 25 near bill's house
Suicune is at Level 40 in HeartGold and SoulSilver.
yes
On Cerulean Cape
LVL 50
Where you find Misty.
No
one and one only
after that, someone at the battle frontier will tell you about latias and latios. then, latias will start roaming kanto.
oh well its at the island were u get grudon
it is not on route 18
Pokemon HeartGold and SoulSilver.
I don't think you can battle Gardenia in Pokemon HeartGold.