YES
Yes.
use a masterball
migrate it from leaf green or fire red
Entei can be found in Leaf Green if your first Pokemon was Bulbasaur and you've beaten the Elite Four. Entei can be anywhere in the wild. There is no exact location.
no
Unfortunately you cannot get the legendary dogs Entei, Suicune, and Raikou in Emerald Green. You can import them into Emerald green by trading from Leaf Green and Fire Red.
it doesn't because you can't get in leaf green because it's kanto leaf green and bellossom is in johto
To get them, transfer them from Pokemon Fire Red and Leaf Green.
you can find them in Pokemon leaf green /fire red after you beat the elite 4 and the champion Charmander - Suicune Squirtle - Raikou Bulbasaur - Entei how do you find them?
level 39 just after gastro acid
102
get a Pokemon with the ability sound proof or a Pokemon with arena trap so he cant run