Just like Christ, Stephen dies commending his soul to God and praying for his persecutors. And v. 58 tells that Saul is a part of his persecutors who cooperates by watching the executioner's clothes.
Saul is not one of the those that stoned Stephen. Although he may have condoned it and was witness to it, he did not commit the act. Stephen forgave those that committed the act. It is not known whether or not Stephen even knew who Saul was. In spite of that it is not said that Saul was forgiven by the others that he persecuted in addition to Stephen. Acts chapter 8 verse 58 - 60 states about his death "But they cried out with a loud voice ansd stopped their ears, and rushed upon him all together. And they cast him out of the city and stoned him. And the witnesses laid down their garments at the feet of a young man named Saul. And while they were stoning Stephen he prayed and said, "Lord Jesus, receive my spirit." And falling on his knees, he cried out with a loud voice, saying, "Lord, do not lay this sin against them." And with these words he fell asleep. And Saul approved of his death."
Stephen did ask that this sin not be layed against them, but he wasn't refering to Saul who was simply holding the witnesses clothes. Saul himself did not do the stoning, although he approved of it. Nor was he (Saul) forgiven by, nor did he ask, of the many others that he persecuted and gave over to torture and death, of them their forgiveness.
St John chapter 16 verses5 -15
The Role of the Advocate
"And now I am going to him who sent me, and no one of you asks me, "Where art thou going?" But because I have spoken to you these things, sorrow has filled your heart. But I speak the truth to you; it is expedient for you that I depart. For if I do not go, the advocate will not come to you. And when he has come he will convict the world of sin, and of justice, and of judgement: of sin, because they do not believe in me; of justice, because I go to the Father, and judgement, because the prince of this world has already been judged. Many things yet I have to say to you, but you cannot bear them now. But when he, the Spirit of truth, has come he will teach you all the truth. For he will not speak on his own authority, but whatever he will hear he will speak, and the things that are to come he will declare to you. He will glorify me, because he will receive of what is mine and declare it to you. All things that the Father has are mine. That is why I have said that he will receive of what is mine, and will declare it to you. a little while and you shall see me no longer; and again in a little while and you shall see me, because I go to the Father."
No where in Jesus' explanation of the Advocate does he state that that this is the Holy Spirit, but that "he is the Spirit of Truth". Nor does he tell the apostles that the advocate could be transfered to another by the laying on of the hands, even though the Holy Spirit can be transfered so. Even when he opens their minds to understand the Scriptures, which is the Old Testament, it doesn't say that he laid hands on them either. The Advocate is one that will explain to the apostles the truth behind the inner teachings, and the truth behind the parables that Jesus taught to them.
As you said in Acts chapter 6 verse 2 - 5 The Deacons
"So the twelve called together the multitude of the disciples and said, "It is not desirable that we should forsake the word of God and serve at tables. Therefore, brethern, select from among you seven men of good reputation, full of the Spirit and of wisdom, that we may put them in charge of this work. But we will devote ourselves to prayer and to the ministry of the word." And the plan met the approval of the whole multitude, and they chose Stephen, a man full of faith and the Holy Spirit." Further you state, "Now Stephen, full of grace and power, was working great wonders and signs among the people."
Being able to work natural law in order to do these works of great wonders and signs, is not the role of the advocate, it is the role of the Holy Spirit. Anyone can call on this power that the Holy Spirit bestows. As I said before Apolonius a Roman could do the same works, as did Bruno Giordano. And even the disciples complained to Jesus that there was a man "not of them" that was working miracles in Jesus' name. Nor did the Advocate come to Stephen, he could recite Jesus words and work great wonders and signs, he could even "see", and he could also recite Old Testament history, but he was not able to do what the Advocate does, explain the truth behind Jesus' inner teachings and words to the apostles.
The next section of Acts describes Stephen after he has been ordained a deacon in Christ's Infant Church.
He is ordained a deacon, but nothing is mentioned about a church, infant church or otherwise. Only that the number of the disciples was growing larger. That is not an indication of the church. The twelve stated that "It is not desirable that we should forsake the word of God and serve at tables." In other words the daily ministrations (spreading to them of the word) to the widows of the Hellenists. Nothing of a church or starting a church there either, as spreading the word is not forming a new religion or church. It is simply a telling of what they had witnessed concerning Jesus, his life, and death, and resurrection.
Saul will soon experience the benefit of Stephen's intercession. Saint Augustine in one of his sermons on this passage wrote, "If Stephen had not prayed to God, the Chruch would not have had Paul."
This is not an indication of anything at all. St. Augustine did not know in fact that Stephens prayers had caused the church to have Paul. It is perhaps St. Augustines thoughts on the subject, but thoughts are not necessarily fact.