Your denial of the Apostleship of Paul does not seem to me to make much sense.
You are also in error about the inconsistent number of Jewish tribes as compared to the number of Apostles as they are quite consistent.
Though the ideal number is twelve of the tribes, on certain occasions when that the tribe of Joseph is split for some specific reason under the guidance of God there is thirteen as the counting of Paul would make thirteen apostles.
The fact that he was a specially chosen vessel is very plainly made in a number of places,by Jesus in Acts 9 and by God in Acts 22:14, and witnessed by Ananias who was visited by Jesus Of Nazareth In Acts 22:8.
Now I know that God/Jesus does not call Paul an Apostle but that Is being a little picky don't you think.
Paul says that he is one and his writing is under the guiding influence of the Holy Spirit the third person of the Holy Trinity, which by the way is not mentioned in the Bible either,so if he is not an apostle the he is a liar and "the truth is not in him " and we would have to disregard every thing he wrote,said and done.
This would eliminate most all of the New Testament especially the church of the Gentiles both past and present, it's organization and it's doctrines.
It would also reflect badly on the rest called the beloved brother and Peter himself affirmed his writings.
I guess what really bothers me about your statement that you won't accept Paul's word under the influence of the Holy Spirit (Who is God by the way) but you require that God say he is an Apostle is very unfair and unreasonable.
Because you see God nor Jesus never called Peter or any of the other twelve apostles either but they like Paul, called themselves apostles ( see 1Peter 1:1, 2 Peter 2:1)
I made no comment about his teaching, and am not calling them into question...
I found in scripture myself what he was called by Christ. I found in scripture what was necessary to be considered an apostle by Peter himself....
The whole thread was helpful to me finding out for myself what Paul's status really was...