Nowhere.
you go to the survival zone
you can trade something for a venusaur and catch a ditto ,put then in the daycare , and that sould give you a bulbasuar
u can only get one based on witch kanto starter u get squirtle=raikou charmander=suicune bulbasuar=entei
you cannot find a bulbasuar ,you can migrate from the leafgreen version
these are the Pokemon i know that are in heart gold version: bulbasuar,charmander,squrtle,caterpie,kaukuana and stelliks.
No
You can catch it in Route 2.
You can't catch Arceus. You can only catch Arceus in Pokemon Platinum.
Trade them from firered or leafgreen.
You can catch Slowpoke in Pokemon Gold in the Slowpoke Well that is by Azalea Town and you can also find them in Tohjo Falls.
you cant you can catch certain gold and silver Pokemon on each game