Is New Testament church leadership singular or plural?

 In response to a friend’s question: in the New Testament, how were churches led? Was the norm one pastor (perhaps with subordinates) or something else?
 
The evidence – in terms of the New Testament – is decisively in favour of a plurality of “elders” or “overseers” (the terms are equivalent, representing local community leaders in Jewish and Hellenistic communities respectively; both were regularly plural bodies, especially Jewish synagogue elders).
 
Here are some “definite” references to a plurality of overseers/leaders:
 
“And when they [Paul and Barnabas] had appointed elders for them in every church...” – Acts 14.23.
 
“Now from Miletus he [Paul] sent to Ephesus and called the elders of the church to come to him.” – Acts 20.17.
 
“To all the saints who are at Philippi, with the overseers and deacons” – Philippians 1.1b
 
“We ask you, brothers, to respect those who labour among you and are over you in the Lord and admonish you, and to esteem them very highly in love because of their work” – 1 Thessalonians 5.12-13a
 
“This is why I left you in Crete, so that you might put what remained into order, and appoint elders in every town as I directed you.” – Titus 1.5, followed by qualifications required.
 
“Is anyone among you sick? Let him call for the elders of the church, and let them pray over him, anointing him with oil in the name of the Lord.” – James 5.14.
 
Here are what seem to be references to a plurality of overseers/elders:
 
“Now I urge you, brothers – you know that the household of Stephanas were the first converts in Achaia, and that they have devoted themselves to the service of the saints – be subject to such as these, and to every fellow worker and labourer. I rejoice at the coming of Stephanas and Fortunatus and Achaicus, because they have made up for your absence, for they have refreshed my spirit as well as yours. Give recognition to such people.” – 1 Corinthians 16.15-18
 
“Obey your leaders and submit to them, for they are keeping watch over your souls, as those who will have to give an account.” – Hebrews 13.17.
 
References referring to an indefinite number:
 
“If anyone aspires to the office of an overseer, he desires a noble task.” – 1 Timothy 3.1, followed by qualifications required.
 
“So I exhort the elders among you, as a fellow elder and a witness of the sufferings of Christ...” – 1 Peter 5.1a.
 
References demonstrating the point in an adjunct way:
 
“I commend to your our sister Phoebe, a deaconess of the church at Cenchreae [near Corinth]...” – Romans 16.1, if one accepts that Phoebe serves in the equivalent church office.
 
“And the Twelve summoned the full number of the disciples and said, ‘It is not right that we should give up preaching the word of God to serve tables. Therefore, brothers, pick out from among you seven men of good repute, full of the Spirit and of wisdom, whom we will appoint to this duty. But we will devote ourselves to prayer and to the ministry of the word.’” – Acts 6.2-3.
 
Analysis
From the above, we know there were pluralities of elders/overseers in Ephesus (Acts 20.17), other cities across Asia Minor (Acts 14.23), Philippi (Philippians 1.1), Thessalonica (1 Thessalonians 5.12-13), Crete (Titus 1.5), and Jewish-Christian congregations in the Diaspora (James 5.14). We can reasonably infer that the same situation existed at Corinth (1 Corinthians 16.15-18, cf Romans 16.1 – if there were deacons one presumes there were elders, after the usual pattern) and the church to which Hebrews is written, probably in Italy (Hebrews 13.17). Indeed, Romans 16.1 and the seeming background of Hebrews lead us to believe that the same system pertained in the Roman churches, specifically. A similar or parallel system, dividing a plurality of teachers of the word from a group of mercy-ministers, seems to have existed in Jerusalem from the earliest days of the church (Acts 6.2-3). If 1 Peter refers to a plurality within individual churches, rather than the net of all elders across churches receiving the circular letter, then a separate group of Asian churches also had a plurality (and this is the easiest reading of the passage, given the other evidence).
 
Of course, this does not at all mean that some elders or overseers did not take leading roles in their teams and churches, based on natural and Spiritual gifting. This is not the same thing as a singular “Head Pastor” or even “Lead Elder”, however – at least as those roles tend to be defined and function. About the only reference to a single pre-eminent local church leader in the New Testament is a negative one, criticising Diotrephes “who likes to put himself first [and] does not acknowledge [John’s] authority” (3 John 9).
 
An additional set of evidences for the above argument can be adduced by considering in detail the way in which priesthood is conceived in the New Testament, but that is both beyond the scope of the original question, and potentially more contentious! For now, we can conclude, quite comfortably, that the standard of New Testament church leadership was a plurality of elders/overseers.