Jesus and the firstborn Word are one and the same. You can't refer to Jesus Christ and not refer to the Word of God, just as when we refer to God, we refer to the Holy Trinity even if not explicitly.
The Canon of Scripture was COMPLETE about 90 AD when John wrote Revelation
Except the Christians didn't know which scrolls were canonical and which were not. The canon was a consensual decision of the Church. It took about 300 years for that to happen. The oldest complete Christian Bible (Codex Sinaiticus) is only decades away from official canonization of couple of dozen scrolls (of over 200+ that were circulationg around) consists of the OT (Greek language Septuagint), New Testament in Greek and the Epistle of Barnabas. Modern Bibles don't have the Epistle of Barnabas.
So, while all the books of the Christian Canon had been written by the end of the 1st century, the actual Christian Canon was not put together until 300 years later, and even then some discrepancies persisted.
Try to follow my train of thought.
I have never said that Jesus is NOT the WORD of God. John 1 clearly states thus.
MY ENTIRE POINT WAS THAT THE GREEK ORTHODOX COMMENTATOR DISHONESTLY IMPLIED THAT THE VERSE IN QUESTION STATED THAT HE WAS THE FIRSTBORN WORD. THAT SPECIFIC VERSE STATED NO SUCH THING. IT DID NOT MENTION LOGOS PERIOD. His argument was that since Jesus is the firstborn WORD that firstborn doesn't have to imply a second born since there was only one WORD of God. It was a dishonest argument since his proof text did NOT mention the WORD but only the phrase firstborn. As a matter of fact, I don't know that the phrase firstborn word even appears ANYWHERE in Scripture.
Regardless,it is a fallacious argument to say that somehow anything in Scripture negates Mary having other children. Even though Jesus is wholly unique in his person, and there isn't another like Him, he was still Mary's blood child. He was her firstborn blood child. His unique nature has nothing to do with whether or not there is a second born child and the natural understanding of things is that if there is a first there is a second - else, you would see something like John 3:16 which calls Him God's ONLY BEGOTTEN SON. There is a difference between first and only, would you not agree?
There was a general agreement before the 300s as to what was Canonical and what wasn't. All of the Hebrew OT was settled long before the 300s. Lists of books circulated before then which included what we have as canonical today. The vote was a formality for the most part.
Regardless, the doctrine of Mary's perpetual virginity did come later than anything written by the early church that was canonical.