A. There are many mods you can use to change your minecraft name (or were I havent looked in a while)
B. There are literally hundreds of places to download herobrine skins
C. Herobrine is a registered account so no **** there is a character called herobrine but it's just some guy on a computer who probably got sick of minecraft a long time ago from everyone calling him a stupid little kid
D. Jesus Fracking Christ learn some proper grammar