How did Jesus pull together such a diverse group without them destroying each other? Read John 17:20-28
1. They focused on Jesus.
The only hope for unity in the church, with such diverse personalities, is that we be focused on Jesus. Some churches have created unity by limiting those to whom they minister. Congregations tend to look and think like their pastor, so variety is not encouraged. In some congregations, those who are different (i.e.--don't fit congregational norms) are expected to change in order to fit into the congregation's template, which is is why very few churches are integrated racially: those who are different understand they are not welcome.
2. Jesus nurtured this great diversity as demonstrated by those whom he chose to follow him.
We don't need to change people, their temperaments, and their qualities to fit into our norms. We only need to realize that the church that focuses on Jesus can handle great diversity. There is no one that the church should be chasing away or expecting to change in order to be a part of our faith family.