A wedding between Wiccans is called a handfasting. These ceremonies are not necessarily commitments for life, as are Christian marriages. They are usually performed by the local High Priest and/or Priestess, but they are only legal if the person performing the ceremony is also a recognized officient by your state/province. Many people have a traditional handfasting, and then have a smaller 'official' ceremony at a later date.
"Harm none" is one of the central tenets of Wicca. The wording comes from the longer poetic version of the Wiccan Rede, and it just means to live one's life bringing no harm to others. Not all Pagans follow these rule, and not even all Wiccans stick to it to the same degree.
The term 'heathen' refers to someone who follows the old Norse pagan traditions. Though it is a Pagan tradition, it is not the same as Wicca. Heathen traditions have been handed down from ancient times, and are not as 'reconstructed' as Wiccan traditions are.