Interesting topic, but there is another "criteria".
It turns out that out of the books considered to be sacred, the NT Bible writers quoted from all 39 books except 3. Excluded were "Ecclesiates", "Song of Solomon" and "the Book of Esther."
Canticles (SOS) and Esther were not considered part of the sacred books at the time of Josephus who mentioned which books were considered sacred. Canticles and the Book of Esther were late additions. But of note, the pagan festivals associated with the celebration of "Purim" were condemned by the orthodox Jews in Jesus' day and seen no more than a takeoff of the pagan Persian New Year's celebration. Of further note, there are two versions of this book, the earlier of which in the LXX contradicts Scripture, so we know the Book of Esther for historical reasons should not be in the official Biblical canon.
That sets up the premise that perhaps the cross-quoting by the NT Bible writers was a means of including as well as EXCLUDING any books they considered not worthy of the final "canon", thus some use the "Apostolic Canon", the Bible's own internal canon to exclude or include certain books. Of course, one should not think that Ecclesiates was "excluded" but simply not included as there were many other "wisdom writings" and apocryphal works about. The "Song of Solomon" though, as noted in my previous thread is definitely a "mysteries" pagan book that gives specific descriptions of several of the mother goddesses, particularly Artemis of Ephesus... So definitely that would have been a difficult book to believe belonged in the canon. But since it was not "included" by cross-quoting by the NT Bible writers, we can exclude it for obvious reasons from the "sacred canon".
http://www.jehovahs-witness.com/10/70787/1.ashx - SOS an Ode to Artemis!
Now some may not like this idea, but it IS there, the subjective canon is there and books excludable for other means are dismissible so I believe it's a relevant and "true" canon that the Christians understood would protect the integrity of the canon, even if some others in authority included other books in the Bible. Of note, the Catholic Bible's include some of the so-called "apocryphal" books as well. ?
I don't have a true position on Ecclesiates if someone wanted to include that extra-apostolically to the Bible's collection of sacred books, but Esther and Canticles are absolutely out.
As a reference in this regard, most libraries especially theological schools have numerous versions of Bible commentaries on each and every book. I'd recommend reading several of the various commentaries, all of which will have a different take on things, of Canticles, Esther and Ecclesiates in particular. It's interesting what is being said about these books in general, but it resonates better when you understand they possibly don't belong in the canon and are not inspired.
JC