Ok...first off, a confession....I have only read the first three pages of this thread, so if anything I add is a repeat of something already posted, my appologies.
I took a class on "what do Mormons believe" once thru church and it was truly facinating. I wish I could recall the video series they showed.
The reason I was wanting to learn about them is because a family moved directly next door to me, and they were mormon. They had children, the mom was close to my same age....so I really wanted to know what I was up against, so I could lead my own children properly if it ever came up.
They are SUCH nice people. I like them very much. They are kind, generous. Willing to help at a moments notice, and to call up any local missionaries to come and help too. But sometimes, I think that is how it becomes so appealing to people. They want a sense of belonging....family. And from everything I have seen, and experienced with the mormons I have been in contact with....they seem to have that in abundance. That can be quite the draw, and very appealing.
MANY years ago, when I was in college in Kansas, I (and two other college friends) were traveling home to Oregon for the Christmas break. We got as far as Spanish Fork Utah at around 3am when my car completely broke down. We walked to a lit up building about a mile and a half away that ended up being a convenience store/mechanics shop. There were two sisters there and they offered to call their dad who owned the place.
He came immedietly....by the time he got us to his house, the wife had already had beds made up for us etc. They were so nice to us when we were in need. The car was not going to be running anymore as the engine block was cracked....but they let us stay, and fed us etc until my brother in law made it there from Oregon to pick us up. Never once did they push their mormonism on us at all....but when it was time to leave, they did want to give all three of us (and my brother in law) a copy of the book of mormon. When we declined, they did not appear offended, and were gracious.
Now, back to the first family I spoke of....(my neighbors). Since they were next door, we spent a lot of time together, and I got to know them quite well. One thing I learned was quite interesting to say the least.
(I can't make this stuff up......)
They wear special 'underwear' called garments. (mhm...you read it correctly) But it gets even better.....these 'garments' have special symbols on them in areas over certain areas (if my memory serves correct) that are meant to protect them. They symbols are from the freemasons.
They only time they do not wear them is when swimming, or bathing. She told me that they are even to wear them when exercising.
https://en.wikipedia.org/wiki/Temple_garment
There are MANY more articles about the special 'protective' undies.....but I went the easy Wiki route.
So yea....they have been some super scriptures shared about not adding to the word of God because the Holy Bible is complete. etc. BUt this is also not scriptural....we are to not live in fear. Also, when Jesus came, there was no need to have anything to connect or bridge that gap between us and God.....that is the Trinity. Which mormons also do not believe in.
Here is just one article I have referenced before....but there are numerous ones out there.
Why Mormons Don't Believe In The Trinity ... Part I
They Judeo-Christian faith believes in the Trinity as a core believe. There is no mention of anything called a 'Godhead' to interchanche with the Trinity of the Father/Son/Holy Spirit.
I hope that some of what I have written helps answer your orriginal question about the book of mormon as well as some others you may have come up with as this thread has unfolded.
Blessings as you continue to seek out the truth. Take care