I have no statistics about what percentage of Mormons living in Clay and Jackson Counties were polygamous, but it was widely believed that it was a common thing.
I had no idea that the Disciples of Christ (IE the Christian Church) was anything other than a mainstream Protestant Church, like the Methodists, Presbyterians, and Episcopals. They do not use the Book of Mormon.
No, no. I did not mean to imply that the Church of Christ (DoC) was affiliated with the LDS movement. It is not. That DoC Key Club advisor answered my questions about Mormonism (raised because I met my wife in Key Club and I respected his opinion) as objectively as possible, but he made it clear that he did not think much of the doctrines. He was a very good, intelligent man and a good Christian.
The designation "Church of Christ" is pretty generic. Part of the reason the name of our church was changed was probably to avoid confusion (and potential legal issues) with other non-related organizations who used that name. The Disciples of Christ use that name, but it is not due to any historical affiliation with the LDS movement. The reason for our rather lengthy designation is to clarify who we are. We believe we are the church of Jesus Christ. We believe we are the very same church that Christ started during his mortal ministry. We believe that, over time, that church became corrupted and a restoration (as opposed to a reformation) was required. That happened through the Prophet Joseph Smith. The "Latter Day Saints" part came as a clarification. It differentiates the church in this dispensation (time period) from the church in Christ's mortal dispensation. "Saints" in this context only means followers of Christ, as the term is often used in New Testament epistles. "Latter Days" means now - what we believe to be close to the end of times - as opposed to (perhaps) "Ancient Days." As an example then, if you ask if Peter was a Mormon, the answer is "yes" and "no.' He WAS a member of the Church of Jesus Christ, so yes, but not the restored church, which has gained the designation "Mormon" from the world (it is not part of our church name) so "no." That is analogous to the question "Was Moses a Christian?" The answer to that, for similar reasons, is "yes" and "no" in that, he was a member of the Church of Jesus Christ (who is the God of the Old Testament) but he did not live in the times when the church gained the designation "Christian" after the actual atonement took place. It's all semantics.
As to the perceptions of polygamy, how many people think Muslims are terrorists today? Though the polygamy issue was not fully openly embraced by the church until Salt Lake, it is quite likely rumor had gotten about. There were many early defections even among top leaders of the church in the Ohio/Missouri period. Many of those who left the church turned against it, and reporting such a practice as polygamy would likely have been part of the efforts to warn potential converts. So I wouldn't be surprised if people knew about it in Missouri. The fact that it was practiced by only a small percentage of the church (especially at that time) would have been irrelevent. The perception would have been much like the perception of Islam today - if the church leaders are teaching it the followers will comply. Of course, what is not commonly known is that one could not just go out and pick a few girls and tie the knot. You had to be "called" by church leaders to marry another woman. (This process is how we select people for any church duty. I was, for example, "called" to be a Gospel Doctrine teacher. That is my current "calling.") So the idea that Mormons were going to steal the daughters was not really accurate. (In fairness, if a young lady was converted, the chance of her becoming a "sister-wife" in some family was certainly there. So the idea was not totally irrational.) But rational, accurate analysis is not the hallmark of mob reactions. It is so in this day of mass communication, and it was much more likely in a time without such media resources.
Where the Islamic analogy breaks down, of course, is that our church leaders were, in fact, actually endorsing the practice, though not yet openly. Only a fringe element of religious teachers in Islam are actually endorsing a direct violent interpretation of Islam. But there are still people who believe Mormons practice polygamy to this day. In fact, there are still people who believe Mormons just hang around in cults in Utah and dress like it's the nineteenth century. A Fedex guy that I see every day was shocked to find out that a very popular local newspaper reporter is a Mormon (and that I was LDS too). He was really shocked when I told him that there are three congregations of Mormons in our town. This is a place where old order Mennonites are a very large part of the community, and a Horse and Buggy is a common sight. So I guess he expected me to be dressed like Brigham Young instead of wearing business casual and fixing broken printers. Whaddayagonnado?