The Lord makes evangelical opportunities to speak for those that are watching for them. For most of us that means the daily one on one talks. For some that means the larger event or location based individual or team efforts. The fact that Paul asks us to pray for these means that the Lord does seek these types of prayers.
Some are given the burden of prayer. It does not say what other positions or responsibilities this person may of held. To be saluted as a warrior of prayer and acknowledged for a particular burden for some specific congregations is illustrative of how Paul's team operated.
Church is where ever people regularly meet. Often we get too wrapped in buildings and architecture and pipe organs and stain glass. A house, a park, a drive-in theater, a school, a rodeo grandstand, a prison cafeteria all work just as well if not better. It is not the type of place that is important but the types of hearts that gather.
There are other epistles that Paul wrote. Perhaps several. Perhaps daily. Paul was not attempting to write for inclusion into some soon to be published New Testament collection. He was not seeking to dominate the other writers with his massive content. He was addressing the needs of the people and congregations that he was placed directly over (Romans possibly being the exception - perhaps planted by acquaintances that he had discipled). His letters were treasured enough that people kept hold of them. By the time the Testament was canonized several years after his death there were enough of these verifiable copies still circulated for them to be included into what we hold today as scripture. Many of these other letters, though I am sure were treasured have either been lost or cannot be accurately verified as there were many plagiarizers of his name and authority even yet today.
2012 - pBiblx2 Field Wise Bible System Version 2.0.9d - GPL3