I contend that Acts 15 revels that there was indeed two churches. There was the little flock Jerusalem church and the body of Christ that, for a time, existed together.
[Acts 11:19 KJV] "Now they which were scattered abroad upon the persecution that arose about Stephen travelled as far as Phenice, and Cyprus, and Antioch, preaching the word to none but unto the Jews only."........
No Gentiles were being preached to. We have to be careful in assuming which church is being referred to in Galatians 2 and Acts 15. There were churches in Antioch before Paul was saved. Paul persecuted the little flock Jerusalem church and they were scattered as far as Antioch. These churches were not body of Christ churches, they were the little flock Jerusalem churches.
[Acts 15:1 KJV] "And certain men which came down from Judaea taught the brethren, [and said], Except ye be circumcised after the manner of Moses, ye cannot be saved.".........
If they came down from Judea, chances are these men who said the Gentile believers had to be circumcised were not from the body of Christ, but from the little flock church (I will explain). ........ [Acts 15:2 KJV] "When therefore Paul and Barnabas had no small dissension and disputation with them, they determined that Paul and Barnabas, and certain other of them, should go up to Jerusalem unto the apostles and elders about this question.".........Paul and Barnabas disputed with the men from Judea, not with the body of Christ members. It was decided that Paul and Barnabas and some of "them" from Judea should go to Jerusalem about this matter. If Paul was going to the apostles and elders, these apostles and elders were from the little flock Jerusalem church.
Paul could not have been disputing about matters within his ministry, but was dealing with stipulations being imposed on Gentile believers by some of the believing circumcision little flock..........[Galatians 1:22 KJV] "And was unknown by face unto the churches of Judaea which were in Christ:".........Paul says the churches of Judea were in Christ; the Jews in the little flock who believed on the name of Christ were in Christ, not just those in the body of Christ. ........Paul was unknown to the churches of Judea who only knew he persecuted them. That is why I said that those who came down from Judea weren't in the body of Christ, the churches of Judea didn't know Paul..........[Galatians 1:23 KJV] "But they had heard only, That he which persecuted us in times past now preacheth the faith which once he destroyed.".......It is very doubtful that those from Judea were in the body of Christ.
[Acts 15:22 KJV] "Then pleased it the apostles and elders, with the whole church, to send chosen men of their own company to Antioch with Paul and Barnabas; [namely], Judas surnamed Barsabas, and Silas, chief men among the brethren:".........When James says they would send men from their OWN company that precludes them from being members of the body of Christ. The apostle and elders sent chosen men of their own company which is those of the little flock, NOT of the body of Christ along with Paul and Barnabas. This wasn't done by Paul alone.
[Acts 15:23 KJV] "And they wrote [letters] by them after this manner; The apostles and elders and brethren [send] greeting unto the brethren which are of the Gentiles in Antioch and Syria and Cilicia:"
[Acts 15:24 KJV] "Forasmuch as we have heard, that certain which went out from us have troubled you with words, subverting your souls, saying, [Ye must] be circumcised, and keep the law: to whom we gave no [such] commandment:".......It is certain that those who said the Gentiles had to keep the law of Moses were from the little flock churches and not the body of Christ members. The apostles and elders of the little flock did not command anybody to go to the Gentiles and say they had to keep the law.
[Acts 15:25 KJV] "It seemed good unto us, being assembled with one accord, to send chosen men unto you with our beloved Barnabas and Paul,"........They sent believing little flock members WITH Paul and Barnabas. There was the little flock and the body of Christ in view here.
No doubt there were two churches here and saying there was just one church is incorrect.
The little flock church are those who believed the preaching of Jesus and the twelve. They believed only on the name of Jesus, that he was Christ, the Son of God, and had life by his name. They were persecuted and scattered under Paul. They were still in existence during the conversion and some of the ministry of Paul. The elders and apostles from the little flock church met with Paul in the Jerusalem council in Acts 15. The dispute arose from the little flock saying that Gentiles would have to follow the law of Moses. The little flock were the ones who disputed with Paul. This question would have impacted Paul and the church who were preaching liberty in Christ and that Gentiles weren't under the law.