There obviously is a difference.
The 12 Apostles were specially chosen. They too had a hierarchy. (Peter being the lead)
Then outside the Apostles you had the disciples. There were two hundred of them. James, Jesus' half brother, was their lead. Then in the individual communities there was another leader of the local assembly.
Many of your comments about leaders seem to be based more on tradition than scripture. The Bible tells us that the apostles appointed 'elders' and also refers to them as 'bishops.' The church in Philippi had a plurality of bishops.
Apostles were made by Jesus and God. Man is to make the disciples...not the Apostles. The 11 chose Matthias to replace Judas. And once they did that he went off into obscurity for the most part. They made a list of discerning criteria that they thought were important and then chose a few guys...and then "spun the bottle" to pick one.
Were the events of Matthias' ministry any less obscure than those of most of the other 12? Can you tell me off the top of your head what James the son of Alphaes or Simon the Canaanite did?
The apostles did this after a time when the Lord had opened their eyes to understand the scriptures. The sin of Achan was determined in the Old Testament by casting lots.
BUT GOD had other ideas.
God chose and made Saul to be an Apostle. The evidence of his Apostleship is much more assured than Matthias' promotion amongst the men.
From Paul's own letter, we can see that the was not one of the 12. Judas hanged himself, and then Christ appeared to many disciples-- including the 11 and Matthias. Paul wrote that Jesus appeared to 'the twelve' BEFORE appearing to him. By saying this he shows that he was not a part of the 12, and accepted someone else as the 12th apostle. Paul was not qualified as a witness of Christ from the time of John the Baptist as Matthias apparently was.
That doesn't diminish Paul's apostleship. But scripture also refers to Barnabas, who was sent out with Paul, as an apostle (Acts 14:4,14; I Corinthians 9.)
Even the righteous teacher Apollos agreed that Paul was the Apostle and that he was simply a disciple. Granted he taught thousands....and Paul was busy spending all of his time in jail.
Do you have a source for this? Be that as it may, Paul wrote about himself and Apollos to the Corinthians, and then refers to himself and Apollos as 'we apostles.'