No - wrong. It’s in the Septuagent. Which means St Paul read it as his Bible. It means most of Jews had access to it, and in fact, the Hebrew Bible you are referring to wasn’t even in existence until much after Our Lord’s resurrection. Bible scholars have no reason to believe the Septuagent was alone in publishing the Apocrypha. So, the Apocrypha were excluded later after the time of Our Lord. Did they eliminate them as they foreshadowed Our Lord? Interesting those who fear those books, no? But make no mistake, they were there when Our Lord walked this earth.
In my view, one of the biggest problems in theology is the misunderstanding of this. St Jerome viewed Macabees in a slightly lesser form even before the 1800s - but even he never denied their influence - even if you don’t think they are in the Bible. All Protestant Bibles used to have the Apocrypha in the back and it is very recent that they were taken out, in the US around the Great Awakening.
So, 1) it is in the Bible; and 2) even if you want to argue it is not, clearly it is not a pagan source.
Second point asked and answered. See point two above. The evidence of liturgical foundations in Tradition and in the Bible have been stated clearly, OK.
Not as scripture. No sir.
Why would you disagree with what your own church says?
For the Old Testament Protestants follow the Jewish canon; they have only the books that are in the Hebrew Bible. Catholics have, in addition, seven deuterocanonical books of the Old Testament. [New Catholic Encyclopedia, Volume III, Canon, Biblical, 29, as quoted in Webster, The Old Testament Canon and the Apocrypha, 24-25.]
Let's look at some rabbinical statements which testify to the cessation of prophecy in Israel in an era before the Apocrypha was written.
With the death of Haggai, Zechariah, and Malachi the latter prophets, the Holy Spirit ceased out of Israel (Tos. Sotah 13.2).
Until then [the coming of Alexander the Great and the end of the empire of the Persians] the prophets prophesied through the Holy Spirit. From then on, “incline thine ear and hear the words of the wise (Seder Olam Rabbah 30).
Since the Temple was destroyed, prophecy has been taken from prophets and given to fools and children (Bab. Baba Bathra 12b).
That last one was referencing the temple prior to the one destroyed in 70AD by the way.
Even the Jewish historian Josephus wrote:
"For we have not an innumerable multitude of books among us, disagreeing from and contradicting one another [as the Greeks have,] but only twenty-two books, which are justly believed to be divine; and of them, five belong to Moses, which contain his law, and the traditions of the origin of mankind till his death…the prophets, who were after Moses, wrote down what was done in their times in thirteen books. The remaining four books contain hymns to God, and precepts for the conduct of human life." [Josephus, Antiquities, Against Apion, 1.8]
The Catholic Church lies.