I do find this exercise to be beneficial. I did struggle with question 5, in that I wanted my answers to come from Acts 1. I selected Act 1:2, which is supported by Matthew 28:20 (Teaching them to observe all things whatsoever I have commanded you) and John 16:13 (Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: for he shall not speak of himself; but whatsoever he shall hear, that shall he speak: and he will shew you things to come.)
With regard to Judas’ replacement, it never occurred to me to question Peter’s actions. In either case, the replacement would be different from the others, Matthias was not chosen by Jesus and Paul, as he himself wrote in 1 Corinthians 15:8-9, was as of one born out of due time and not meet to be called an apostle. As to how many were qualified, Luke was silent; he only tells us that two were chosen.
If there was any dispute as to whether the apostles were right to replace Judas, it seems to me that Luke would have mentioned it, as he did in reporting on the Council of Jerusalem in Chapter 15. James and John were strong personalities, as I am sure several others of the some 120 were. But just before Peter stood up, Luke says they all continued in one accord. So if Peter was wrong, they were all in on it together. I do not believe that to have been the case.
Peace,
Rich