Are you allowed to wear it/recolour it etc?

Yes, he's said on multiple occasions that his set can be used

No, because it is a set made for and belonging to someone else.

Or maybe it can be :s

Listen to MegaCash.

You can do whatever you want with it (hampa stated that), but do not claim that it's of your own work, and don't try to sell it (general rule).

I heard before you can wear it but people may still ban you. Is that true?

No as EJM said before you can wear it recolour it and edit it but you can sell and no one can ban you if hampa said that.

You can use it anytime, as long as you say that it isn't yours and it is someone else's....
Also, if you even try to edit it so hardly until it doesn't look like it's hamap's head.
You can't still say that the texture is your, but you may say that the texture is EDITed by you.