Yes.
NO
arceus, dialga, palkia, mesprit, azelf, uxie, creselia, groudon, kyogre, rayquaza, entei, raikou, suicine, moltres, articuno, zapdos, ho-oh, lugia
moltres obviously as it is a legendry
The Bird Trio Articuno, Moltres and Zapdos at Seafoam Islands, Top of One Island and Power Plant respectively. Mewtwo, at Cerulean Cave after getting the Ruby and Sapphire to Celio at Sevii Islands. Ho-oh and Lugia in events.
There is no legendary Pokemon in Charge Stone Cave.
yes
No, you cannot get Lugia on Pokemon Yellow.
You mean Masterballs? There's only one you know.
Shadow Lugia is a fake pokemon. You can not obtain a Shadow Lugia in any Pokemon Game (so far). Shadow Lugia is just another rumor pokemon.
You can't get Dark Lugia in Pokemon Silver, Gold, or Crystal. You can get Dark Lugia in Pokemon XD though. For Pokemon Silver, Gold, and Crystal it is just the regular Lugia.
you cant get every legendary of Pokemon without cheats or migrating and trading with people
lugia isn't in Pokemon leaf green