There is no shadow pikachu in either one of those games.
Pikachu
Nope, you can't get pikachu as a partner Pokemon, but you can get other cool partner Pokemon likecranidos- my personal fav ;)
You can find it in many places, including Crysta cave, the cargo ship, boyleland volcano,the Chroma highlands, chroma runes, and chroma road.
Pikachu's name is Pikachu.
A Pikachu evolves from a Pichu.
A male pikachu can breed with a ditto or a female pikachu
There isn't such a thing as Pikachu 2. There's Pichu, Pikachu and Raichu, not Pikachu 2.
To breed Pikachu you need to leave a male Pikachu and a female Pikachu (or a Ditto and a Pikachu) at a daycare. If you wait a while, the female will be holding an egg.
Pichu evolves from pikachu than pikachu evolves from raichu.
Ash kill Pikachu because Pikachu is useless.
pikachu
If you're talking about Ash's Pikachu then yes, Pikachu is a boy.A Pikachu can be a girl or a boy, but referred as an "it" in many of the games and in the Anime. Ash's Pikachu is a male, for his tail does not have a notch in the side.