I've bolded the parts of your reply I'm referring to.
I doubt there's a definitive list of the ECFs but they're not just the apostles. Wikipedia says this:
"The historical period during which they flourished is referred to by scholars as the Patristic Era ending approximately around AD 700 (Byzantine Iconoclasm began in AD 726,John of Damascus died in AD 749)."
If there is, as I believe too, one Spirit that guides us, how come there is so much diversity, not just among denominations but also between everyone within each church. Everyone has a different take, to varying degrees, on God but yet there still guided bu the same Spirit. Perhaps one way to reconcile this is to look at the word "guide". If a guide takes a group around somewhere, everyone follows him/her and ends up at the same destination but they still walk their own paths. They don't form a line and walk in each others footsteps.
Edited to push the analogy too far. Just as on a guided walk, we tend to team up and walk alongside like-minded folk.
This is what we have heard :
The revelation of Jesus Christ, which God gave him to show to his servants THE THINGS THAT MUST SOON TAKE PLACE. He made it known by sending his angel to his servant John, -Revelation 1:1
I was IN THE SPIRIT on the Lord's day, and I heard behind me a loud voice like a trumpet -Revelation 1:10
saying, "Write what you see in a book and send it to the seven churches, to Ephesus and to Smyrna and to Pergamum and to Thyatira and to Sardis and to Philadelphia and to Laodicea." -Revelation 1:11
What take place in the seven churches, take place in different period of time, beginning from Ephesus till Laodicea.
As we have been told to listen to the Spirit:
He who has an ear, let him hear what the Spirit says to the churches. -Revelation 2:7
Though we are now living in the period of church of Laodicea, we together with the early church fathers must listen to what the Spirit have said to the churches, beginning from Ephesus to Laodicea.
The relevancy what has been spoken for us, is what is written and send for the church of Laodicea.
Our Lord Jesus Christ through the Holy Spirit have spoken to all the churches.
It is true that many have ears but many have not heard what the Spirit have spoken to the churches. Why ?
These many people who have not heard what the Spirit have spoken to the churches because they have not received the Spirit who is from God.
As we have heard:
This is what we speak, not in words taught us by human wisdom but in words taught by the Spirit, expressing spiritual truths in spiritual words.
The man without the Spirit does not accept the things that come from the Spirit of God, for they are foolishness to him, and he cannot understand them, because they are spiritually discerned.-1 Corinthians 2:14
Yes, indeed, the Spirit of truth guides us into all truth from the church period beginning from Ephesus to Laodicea. ( Revelation 2:7 till Revelation 3:22)
Listen to what has been said to the seven churches, then you will understand what our Lord is concerned about what happen in those times of church history.