“I notice the early writings on Mary were not included in the canon.....so what does that same about them??”
It means that those writings were/are not necessary to our theosis. Many of them are part of or expressions of Holy Tradition, however. The Latin Church has two Marian dogmas, the Immaculate Conception and the Bodily Assumption of the Theotokos into heaven. As I understand it, acceptance of these dogmas in the Latin system are necessary to salvation. We do not have those dogmas, though I don’t know any Orthodox Christians who do not believe in the bodily assumption of the Theotokos.
I don't know either regarding rcc, but I do not that is not a requirement of salvation based on the Word.
Must have gotten started somewhere before the SPLIT.