yes and in most cases it is illegal. In all cases it can get you banned and hated by other players.
To get Pokemon in Minecraft you must get the Pixelmon mod, but sense you currently cannot install mods in Minecraft Xbox 360 Edition, it is impossible to get Pokemon in Minecraft Xbox 360 Edition.
Unfortunately you cannot get the Pixelmon Mod on Minecraft for the XBox 360, this is because you cannot mod the XBox version currently.
The Aether is a mod and you can only get mods for the PC version
No, sadly you can not make an Aether portal on the Xbox Edition of Minecraft because the Aether is part of a mod. As of now, the Xbox Edition of Minecraft does not support mods.
Currently Minecraft Xbox 360 Edition doesn't have mod support so no mods can be installed, but when it is added, the creator of 'mo creater' will probably release it soon after.
No, you can't mod the XBox 360 version.
You can't mod the XBox 360 version of Minecraft.
You can make a carpet on Xbox 360 Edition of Minecraft using wool.
No, you can't install third party content on Minecraft XBox 360 edition.
Unless there is an adventure map that has been made especially for minecraft 360 edition then no. what you are referring to is what I believe to be called a mod or modification which changes up your game in magnificent ways however these have yet to be implemented into 360 version of the game.
I do
Herobrine has never been in Minecraft, any edition.