The Biblical form. I see a role for three 'categories' of people:
1. The saints/the Brethren/disciples. There are many occasions in Acts where, 'the brethren' do many things. They send back the prophet Judas to Jerusalem. They recommend Silas to Paul. They sent a letter of recommendation for Apollos. They brethren received Paul's group gladly. Many regular church decisions are made by 'the brethren' in Acts.
In Acts 15, there is a meeting of the church and regular people in the church speak up about it. Some of them were wrong, but they could speak.
A disciple named Ananias also baptized Saul of Tarsus. God used this disciple to heal. In James 5, we are to confess our faults 'one to another' and pray one for another.
Most epistles are addressed to churches as a whole, who collectively had a responsibility to obey the instructions therein. Most epistles aren't written to leaders exclusively. Timothy and Titus did receive personal letters.
The Bible never teaches that clergy, elders, etc. are the exclusive teachers or ministers in church. Someone who is not an elder could be gifted to teach, and I Peter 3 commands good stewardship of gifts. One should teach BEFORE becoming an elder, since elders are already supposed to be 'apt to teach.' I Corinthians 14, the one long chapter that says what to do in church doesn't even mention elders (or 'pastors'). It does give instructions to prophets and 'every one of you' who would speak in church, telling how to minister 'unto edifying.' Church ministry is not supposed to be pulpit-centered and clergy centered, with one person doing all the talking and everyone else listening, unless we mean one Person ministering through the various members of the body.
2. The elders of the church/overseers.
In the Bible, we see that the apostles would appoint elders to oversee and pastor the churches.
3. Apostles.
This principle is still important on missions fields and where new churches are formed. Paul and his coworkers had a 'measure of rule' in Corinth because they had introduced the Gospel of Christ there. And they would instruct the people. Paul even judged a case about a sin by distance in I Corinthians 5, chiding the congregation for not having their own judges in the next chapter dealing with law suits among believers.
In Acts, we see apostles handling a lot of the affairs of the local church, collecting money and feeding widows. But later, we see they had deacons feed the widows and elders collected money from out of town. As others matured, the apostles could devote themselves to prayer and being witnesses of the resurrection. The apostles stepped back from handling the affairs of the church. When Paul came to town in Acts 21 amidst controversy, the apostles referred him to James and the elders.
Missionaries may have to handle a lot of the nitty gritty of new church plants at first. But as churches mature, the brethren handle it. At some point, men within the congregation mature to the point where they can serve as elders, pastor, and oversee the flock. Some also mature to serve as deacons to serve in various ways.
