In answer to your rhetorical questions.
May I suggest that it's likely a mistake to think of the past in terms used in the present. As my Ancient History teachers kept reminding us, "The past is another country, they do things differently there."
Your OP asks:
"Who was the president of the first Century christian Congregation after Jesus death , , the Secretary ,the Treasurer ,the Field Overseer ,the District Overseer"
There are easy answers to those questions. Both the NT and other sources indicate James became the leader of the Jerusalem congregation, and after him other members of Jesus' family seem to have occupied that. All the functions we expect to see in an organisation today, can often be found in some parallel way in first/second century organisations. For example, Marty E.Stevens, two books will allow a reader to understand that religious organisations in the past were quite complex, as they are today
Of course, modern religious organisations also have to respond to the increasing complexity of national laws and regulations and a Secretary of a large religious group will likely have to attempt to ensure compliance to those rules and regulations.
As Stevens discusses, there were equivalents of accountants attached to both the Jerusalem Temple and most pagan temples in the West Asian/ Mediterranean world.Records were kept to account for everything
As we understand the times, most meetings were held in house churches, often provided by high social status Christians. I think its reasonable to expect that membership contributions were accounted for separately from that patrons household accounts. If as some texts suggest, the early church supported some members (like widows) some records would have been kept. Later, after the legalisation of early Christianity the Emperor and his family began to provide the funds to build basilica's (churches) as meeting places. We can be confident that the Emperor's staff would've required an accounting of the funds provided.
"were the Lawyers protecting the Congregations from secular Authorities."
There were lawyers (of a sort) in the Roman Empire., and yes! we do have records of delegations to Rome to discuss legal problems with the government. And, after the 'legalisation' of the church, there were even more of these delegations as intra-church disputes over ownership of church buildings, who had to right to lead the local church, and doctrinal matters were sent up to the Emperor's staff for settlement.
Were there Circuit/District overseers? Our best records demonstrate that there were people sent out as special representatives for a lot of reasons.
The structures of both modern mainstream churches and the JWs reflect the need for a similar regulation of "religious" life and activity.
I could keep going for page after page - we may like to imagine early worship as 'simple' but in fact it was often very complex. Think of Israelite religion, When David turned the Kingship over to Solomon there were 38,000 Levites serving a religious function including 4000 soer (that Stevens translates as 'gaters' (organisers). 1 Chronicles 26:14 says one of these soer was, 'an advisor with prudence,' make what you will of that term. It was not simple task to do all the things that Temple worship required, including getting rid of the blood and guts of sacrificed animals