1) I think you mean griefers always destroy your buildings, just because you are hacking, doesnt mean you are going to grief

2) To get the first rank, you just need to type:
/member [Your email address here]
and it will give you a code to enter on http://www.womrealms.com/
then it is 500,000 rep to get to the next rank (i think)

3) To change your skin, you need to have bought the full version of the game, without hacking, it is impossible to change your skin when you just play classic