Great. See, we already agree.
Let us keep the focus on our discussion. Others can believe various other erroneous doctrines and ideas, yet that should not impact our discussion.
I hate to ask for further clarification, but alas, I am going to.
I will try and address the various "errors" that you listed below.
Would you make the argument that Jesus misrepresented something? Or, would you say that the error lies with human interpretation, rather than Jesus?
To imply that Jesus would misrepresent various items of discussion would lead to a contradiction in the nature of God. God must be Truth, otherwise, he is a liar and a deceiver, and not God. Therefore, logically, if we agree that Jesus is God, then Jesus cannot misrepresent anything.
Two questions regarding this passage: 1.) What purpose is this being presented? 2.) You are aware that Jesus did not have "brothers," however, this passage references "brethren," as Hebrew custom was to call any close relative "brother/sister," "brethren," etc.?
And here is where context, both within passages, biblical books, and history come to matter. Jesus at this time is speaking to an audience of locals, yes? To these locals, the smallest seed is a mustard seed.
Does this mean Jesus was lying or wrong (scientifically)? Of course not. He was addressing a specific audience, in a specific location, relating parables to what they could easily identify and grasp. This is contextual evidence.
What specific passage are you referencing? (I would go ahead and consider passage/book/historical context, as that will be a significant foundation for my "proofs" and arguments)
Was Jesus misrepresenting, which would be dishonesty, or was He relating parables to the targeted audience and their respective knowledge? I would obviously argue the latter as true.
I did not imply that, as humans, they were forever infallible. You see how by simply avoiding specific clarity (which I did purposefully) how you extrapolated my meaning to a different connotation?
I think this is your personal error when it comes to doctrine regarding inerrancy. You have taken inerrancy, and made it "infallible," meaning free from any and all errors, including minute detail comparison (lack of disparity). "Infallible" would only apply to the Apostles, and their successors when speaking under the guidance of the Holy Spirit. After all, they are still humans, and capable of sin (while they lived).
This is a common falsehood/misunderstanding. We actually have several accounts of first and second century persons explicitly referring to Matthew and the author of the Gospel attributed to him. For example, Papias, bishop of Hierapolis in Asia Minor, refers to Matthew and Mark as the authors of the first two Gospel accounts, in 130 AD. We also have similar confirmations from Irenaeus. Around the same time, we have statements in "Muratorian Canon," a document of Roman origin, also giving this confirmation. Likewise, Clement of Alexandria and Tertullian also describe early Christians, priests, and churches, ascribing authorship of the Gospels to their respective ascribed authors.
Let us also consider historical context. Matthew was a tax collector. Who, among the Apostles, was most likely, based on occupation, the most literate? Matthew's job would have entailed documentation and detailing, through written records.
Furthermore, what is the likelihood that hundreds of people would have ascribed authorship, for four distinct books, to the exact same authors, respectively, without any disagreement? The probability would demonstrate that the attributed authorship(s) are correct.
How do you know that the documents are trustworthy?
Agreed.
Such as....?
There are many things here.
Let us start with a simple one: I am aware that Jesus did have brothers. Why would you think otherwise?
Let us cover one thing at a time.