The campaign is based on the concept that the players are trying to make the world a better place, as such the players should general be good, leaning towards the Law, Good or Neutral. That being said there are not restrictions on individual player alignments so long as they are ultimately good.
The party will need to coordinate their background. The players need to have established relationships from their backgrounds. The relationships could be as simple as having worked together in the past, but in general each character should have at least one or two relationships with other characters in the party.
There will not be PVP in this campaign. This is a friendly game. Backgrounds intended to betray the party or characters designed for such will not be allowed.