We know for a fact that he spoke Greek (Acts 21:37) and Aramaic (v. 40) in addition to Hebrew. But no evidence of him writing in it. And in regard to the remainder of your post, there is no evidence that any of the other apostles could even speak Greek. Sure, anything is possible I suppose but common sense tells us they would have first written down their accounts in their native tongue; one they were intimately familiar with. More so since these accounts happened in a land were Hebrew was the primary language.
In any regard, they certainly did not think in Greek, therefore everything they saw and heard had to be translated by someone(s) fluent enough in the Greek language that they were able to "coin" words and phrases to match Hebrew words and phrases as closely as possible. And even then, the Pagan characteristics of the Greek language limits the ability to completely convey the message from Hebrew as we've seen.
>> but common sense tells us they would have first written down their accounts in their native tongue<<
Common sense tells us the Holy Spirit would have them write in the language that would reach and relate to the largest possible audience which would be Greek.
But no evidence of him [Paul] writing in it [Greek].
I, Paul, write this greeting with my own hand. (1 Cor. 16:21)
See with what large letters I am writing to you with my own hand. (Gal. 6:11)
I, Paul, write this greeting with my own hand. (Col. 4:18)
I, Paul, write this greeting with my own hand. This is the sign of genuineness in every letter of mine; it is the way I write. (2 Thess. 3:17)
I, Paul, write this with my own hand. (Philemon 19)
And, in any case, we also know that Paul employed an amanuensis, as was customary. We even know the name of one: Tertius (Rom. 16:22). Whether Paul wrote entire letters with his own hand is nothing but a distraction from the real issue: If the New Testament was written in Hebrew originally, why are there thousands of Greek copies, but zero ancient Hebrew copies?
And in regard to the remainder of your post, there is no evidence that any of the other apostles could even speak Greek.
The books of Luke—his Gospel and Acts—are addressed to a "Theophilus." That is a Greek name. I wonder what language a man with a Greek name might have spoken.
Sure, anything is possible
See, this is why it's so difficult to take your arguments seriously. On the one hand, you want us to believe that it's possible, that the New Testament was originally written in Hebrew, even though you have no empirical evidence that was the case, only conjecture. On the other hand, the overwhelming number of Greek copies makes it not only possible but probable that the New Testament's original language was Greek. Yet while you admit that "anything is possible," you dismiss the possibility out of hand.
Inconsistency is the sign of a failed argument.
And even then, the Pagan characteristics of the Greek language limits the ability to completely convey the message from Hebrew as we've seen.
You have to be careful taking a stand in which you dismiss a language as 'pagan.' Chart below shows the progression of the Hebrew. I am sure you will note the later Hebrew and then Aramaic were influenced by neighboring pagan empires to include Babylon? Even if you look at the paleo-Hebrew pictographs there is linkage to the language used by the Philistines, which if you look at their history they came from 'Greek' environs.
So what I think we see as the Hebrew language progresses, it gets closer to other languages in the surrounding regions. Amazing to look at as God promised to bring salvation to the Gentiles and as the nearing of the First Advent of Christ, we have an empire which has multilingual subjects. And the fact (as you look at the chart) the Hebrew of the time of the First Advent starts to become more 'integrated' with the Greek.