Let's not be too self-important. We all need to do the observation for ourselves. Nobody should ever accept another's biblical research for themselves. I think that is true for all areas of knowledge actually. At the same time no person can live in isolation and it is important to consider others' work. For that I thank you.
If you want to believe there are contradictions, then no more thought needs to be given. You can say, I have detected a contradiction and leave your analysis at that.
For anyone who really wants to know if these are really contradictions, more thought and consideration is necessary. This is true in any realm of knowledge.
When you look at the facts of Hebrew culture and language, one quickly sees that things are complex. Christians haven't created this complexity. It's just there. To make the issue more difficult, ancient people didn't use language in a precise way. They weren't trying to make sure that people 2000 years later would easily understand them. We come from a very different culture. We communicate differently and to understand ancient writing we have to do our best to understand how they communicated and thought about the world.
This is especially true in the realm of time reckoning. They weren't meticulous time keepers. They didn't use a standard count of years like we do now. Years were identified relative to the reigns of kings. Controversies and intrigue made that a difficult task at times, and neighboring countries often followed different rules. Same for accounting of days.
I can't say that any of the explanations given by Christian scholars are correct. If we look at it logically though, if any of them are possible and have a basis in lingual or cultural facts, then an assertion of contradiction can not be stated with any measure of confidence.
My last point I raised in my previous post is that each gospel describes the day of Jesus' death as the day of preparation. So you can't say that John somehow is changing his story to fit into some meta-narrative. There is variation in the accounts of course but the same picture is being painted.
From my reading, I think it is even possible that both Jesus and the Jews who arrested Him could have observed Passover within the timeframe set out in Leviticus. There are hours within which each group could have observed Passover and still followed the narrative we have.
I know you have said you have done all the research there is but I didn't see anything you wrote that explains that the Passover lasted a week with meals every day. Only one involved the lamb but feasts were observed for 7 days. There is also an issue with the way the Jews accounted for Sabbaths. Many scholars, secular included, believe that there were back to back Sabbaths during this time. So a lot is going on. Treating the events as totally straightforward isn't warranted whether or not you believe there to be contradictions.
Like I have said before. I don't require that God spells all this out for us. We have brains. We can observe and study and think through these chronologies. It is fully within God's character and to test us, and we see God doing that in several places in the Bible.
Anyway, Peace. Go Mavs.