in regular minecraft you have to "summon" herobrine.
in Xbox 360 edition you can unupdate the game to summon herobrine but i am unsure if u will ever see him i know you will see burning trees and will find missing torches and stuff and possibly creepy signs in random places.
i have not played pocket edition lite but if it is connected in any way to 4j studios then it might have been removed. you can always try summoning herobrine and find out that way.
No, since you can't mod the XBox 360 version, you can't get Herobrine.
Herobrine is not real and has never been real in any edition of Minecraft, or in any version of any edition. Anyone that tells you he is real is lying, and Notch did confirm that in a certain tweet on his Twitter, which you may find quoted on the Herobrine page on the Minecraft Wiki.
No you cannot
They are not in the present edition, but they may be in the future update 4.0
make the nether reacter
The Nether Core
you could find a pool of lave place water then it turnes the lava to obsidian to get it you have to mine it up with a pickaxe
it has not been added
The same way you get iron on Minecraft PC/Desktop Edition and Xbox Edition. Just try to find a cave.
If you've added Herobrine to your game via a mod (and there are many), the exact way to find him will be explained in that mod's text. There is no Herobrine in the unmodded game.
Creepers have not yet been implemented in Minecraft Pocket Edition (as of 0.3.3) however in the planned changes list it is mentioned that they may possibly be implemented in 0.4.0
Same place as the computers vanilla Minecraft.