I'm re-visiting the issue to see any new light can be shed on it.
Till now, I'm on the stand that the deuterocanonical/apocrypha books remain open to be adopted by Protestants as authoritative. But I do not enforce or restrict that to be the case for all Protestant or all non-Protestant.
It didn't matter at that time because when I reflect upon myself, I failed to live up to the 66 books of the Protestant Bible, thus whether there are additional books or not is not much of a concern. I was more concern with my life whetjer am I living rightly; whether am I conforming to the authoritative works (whether 66 or more books).
But this issue cannot be left open when it comes to doctrines, as I realized. Previously I hold that whether it is 66 or more than 66 is up to respective tradition to adopt. And it's up to their own use of their own canon for their own theologies.
But now, it is impractical to hold on to such theological relativism if one is to be coherent theology and doctrines. So, I will dig into this. I will refer the disputed books as 'deuterocanon' primarily in order to distinguish them from other 'apocrypha' (Acts of Thomas, Acts of Peter etc).
1) Find out the criteria for canonization of Luther and Calvin. Since they appealed to Jerome, I will look into Jerome's works. So far, found out that though Jerome's list of canon is almost identical with Protestant's list.
2) Criteria for canonization for Jerome. His disagreement with Augustine. His submission to Pope Damascus.
3) Rabbinic texts on Hebrew canon. So far, there are evidents that these Rabbis use the apocrypha as authoritative up till the 4th century.
4) The council of Carthage (c.397) which listed the apocrypha as canon. Since our NT listing and orthodoxy depends alot on these councils.
5) Gelasian Decree (5th / 6th century) which listed the apocrypha as canon.
6) Early theologians such as Origen, Athanasius, Tertulian and etc's perception of the deuterocanonical books. Since our NT listing depends on their list of NT canon, so it is important to check with them.
I think if to study this issue from the Christian's point of view, I have to assume two fundamental assertions. First is that Christian faith cannot be separated from church history and tradition. Thus, I will study this from the tradition of the early church. That will help to avoid to look into the arguments by ancient non-Christian Jews on the Hebrew canon.
My second assumption is that doctrines should be developed on historical basis rather than theological. I use both term strictly. For eg. when I say 'theological', that means I cannot determine which books should or should not be included in the canon for theological reason such as they contradict Protestants' heritage. My aim is to find out what was the most prevalent perception the early churches had on the deuterocanonical books.
Wish me luck!