Spiritual gifts are given by the Holy Spirit and authority flows from the gifting. If that person uses their gifts in a way that is ungodly (as shown through the bible - fruits of the flesh vs fruits of the spirit), then the decerning christian will know the source of the gift. It is not necessary to have some human “authority” to make some determination.
The establishment of the Jewish canon is still of some debate with some supporting the date of the fixing to be after Jesus’s ascension and others many years prior to his birth (Hasmonean dynasty). It can be reasonably argued that the Torah was canonized and available to Ezra (444 BC). Rabbinic tradition asserts that the Prophets (Nevi’im) was canonized at the conquest of Alexander the Great (332 BC). It is the Writings (Kesuvim) that has the most uncertain end date for canonization. While virtually all the Writings were regarded as canonical by the time of the destruction of the Temple in 70 C.E., arguments continued regarding the status of Proverbs, Song of Songs, Ecclesiastes, and Esther, and these disputes are attested in rabbinic literature. However, we do know that the youngest book in the Hebrew Bible is the book of Malachi, written about 400 BC. The Apocrypha and Pseudepigrapha not being accepted as canon by Josephus.
The authority rests with the Holy Spirit as to who is called and who is gifted.
Order only comes when Christians follow God’s will, not some man made tradition or authority.
At least that part is correct. What is God's will?
Don't forget Ephesians 4:5. A church that doesn't baptize isn't the Church of Jesus Christ.
As a side question: the real First Corinthians is discovered. Does it become canon, why or why not?