I'm not necessarily arguing that Biblical interpretation is always really easy and that we have near 100% confidence about its meaning. I think there are difficulties given the passage of time and differences in culture and language. I just think, whatever the confidence % is for a particular verse, it is higher than our confidence can be about whether or not a particular Biblical character said something or did something. In other words, despite the various interpretations of what Jesus meant by "fulfill the law", I think we are closer to knowing what that meant than we are to knowing whether Jesus actually said those words and in what setting he might have said those words (or whatever other historical questions a historian might ask).
I think we have more evidence that can help with the interpretation questions than we do for the historical questions. Proper interpretation can even be an important piece of evidcence to answering a historical question, so if interpretation is really difficult then that just makes the historical question even harder. Tabor's historical argument that Paul's message diverged from Jesus' message requires a proper interpretation of both Paul and Jesus.
I'm not sure the varied interpretations of Matthew 5:17 means that we can't have confidence in what Jesus meant by "fulfill the law". We don't need to give each opinion equal weight in the discussion. I think we can think of some other topics (the only ones coming to mind right now are political so I won't' mention them) where there are different opinions out there where I assume you'd agree that we can have high confidence what the right answer is.
Admittedly, I say all of this with far more experience in Biblical interpretation than i do in thinking about the historical questions. I could be overestimating how hard it is to make some of these historical claims. So, maybe our disagreement isn't so much on how confident we can be in interpretation, rather in how confident we can be on the historical questions.
That makes sense and I agree that historicity is more difficult than interpretation. I still like the exercise of attempting to simmer things down to what Jesus most likely taught versus what was layered on by scribes, Paul, etc. who had their own agendas. For example, there is nothing is the Gospels that compares to 1 Corinthians 14:34-35 and based on Jesus' treatment of women, it's probably not something he would have taught. Would you agree with that?
Strangely, despite being a member of a congregation that leans pretty conservative on women's roles in the church, I haven't spent time studying that issue. I agree at first glance Paul seems to be out of line with Jesus here. But, since my bias is to assume that Paul's primary mission is to take the Jesus way of life and apply it in new (largely gentile and former pagan) contexts, then I'll tend to look for reasons why Paul is NOT out of line with Jesus,
As I start to look at this, it does appear that there might be some validity to a more skeptical view of these verses. Some scholars have argued that these verses don't belong and weren't original. Others argue they don't belong as verses 34-35, but should come at the end of the chapter. Many obviously argue they are original and belong right where we have them. To me, it sounds like there's enough noise to not make any definitive church congregation decisions without a ton of study, especially if those decisions are going to contradict something clearer from Jesus (and from Paul elsewhere) like, "love you neighbor as yourself". So, I agree this looks, at worst, anti-Jesus and, at best, complex. Having said that, while I'm comfortable with some Biblical "contradictions", I'll do my best to harmonize this with Jesus to fit my bias.
The initial problem is that It sounds anti-woman and Jesus doesn't appear to be anti-woman. However, it's possible it is not anti-woman. Women aren't the only ones being told to be silent. The preceding verses also talk about those speaking in tongues and prophets to be silent in certain situations. The women are being treated the same as whoever is in those groups and I don't think interpreters see Paul's instructions to them as being anti-Jesus. Paul certainly isn't being anti-tongue or anti-prophecy. He spent the bulk of this chapter talking about speaking in tongues and prophesying. Just a few chapters earlier (11:5), Paul talks about women who pray and prophesy, so I think it's clear that this command to be "silent" is a little different than what it might appear.
In verse 26, Paul says "Let all things be done for building up" and then he ends 40 with "But all things should be done decently and in order." That, in the context of "When you come together", seems to be the main point of this section. Those ideas bookend a section that has this in the middle (verse 33a): "For God is not a God of confusion, but of peace." It is then interesting to take a look at different translations and their paragraph breaks. The NASB, ESV, and NET all put 33b as the start of a paragraph with 34-35. However, the NIV puts 33b as the end of the previous paragraph. That reads very differently to me because 33b sounds like a universal statement, while the commands about tongues, prophecy, and women come off as more specific insider talk between Paul and Corinth.
So, I think Paul uses the three examples of tongues, prophecy, and women in church gatherings in order to make a point about God desiring order and peace and building up the body. The women is one application of that larger principle. When you ask, "it's probably not something he [Jesus] would have taught," I guess that depends on what you think Paul is teaching. I think the principle that God desires order, peace, and building up when his people gather is something Jesus would support. I suppose it's possible that Paul then misapplies the principle to his new gentile/recently-pagan audience and could then become something Jesus wouldn't teach. And I definitely think modern interpreters should be very careful what lesson they get from this and try to apply to their own context. If they can see the principle about order, peace, and building, then that's what a modern church should apply to their meetings rather than a straight-forward "all women should be silent in church."
I think Jesus challenges some cultural norms, but he also doesn't completely overturn everything. He cared a lot about how people were treated. He especially spent time addressing how insiders/leaders were treating outsiders and those who they were supposed to be leading. I think it's possible that's what Paul is doing here. He's not admonishing the single group of "women", but has instructions for particular people who are acting a particular way that must have been hurting other people's opportunity to be built up and to experience order and peace in their gatherings.
So that's my biased interpretation for now. Like I said, it does seem like there could be good arguments that this doesn't even belong as being originally from Paul. I mean, it's pretty weird to have a whole chapter that repeatedly talks about tongues and prophecy and then throws in one comment at the end about women disrupting things. It seems out of place. If it doesn't belong, then that gets at the questions you're asking about simmering things down to what Jesus would have supported. It's an interesting exercise.