Turn the Xbox on it's side or change it in the opitions.
You can use the related link below to go to the minecraft.net skin chooser. You then log in and upload the .png file of your skin.
You got to buy gold membership
it depends if u cheered enough
go into a match press start go to armoury then scroll down to colour the move the selector over the colour you want and press A
yes i think you can by contacting them and giving the name you want