I am not the ultimate authority but will try. I actually think you can find those answers and much more, eventually, via the links at my site including to official and other sources, but:

1. 2nd bullet here: http://lukecall.net/e9223372036854587340.html , etc: I was born to it, but my ancestors on various branches went through a process of investigation and prayer to decide for themselves, and really I had to do the same thing to stick with it (as in the above link and its subsequent ones), as it is a significant commitment (and hugely personally rewarding: peace in this life, and hope of Eternal life in the world to come, really). Also Mormonism is a misnomer: Mormon was an ancient American prophet whose abridgment etc is called the Book of Mormon, but ... details on the name here: https://newsroom.churchofjesuschrist.org/style-guide .

2. We believe that a) Christ created this world and others under the direction of the Father (they are one in purpose and act in harmony, and both speak authoritatively since Christ has received the Father's delegated authority to speak as God to us); b) Jesus Christ is the Jehovah of the Old Testament; c) He was known to Adam and Eve and those of their posterity who chose to follow the truth, but others chose not to, and various beliefs spread among the nations at different times; d) that God has given truths to his children at different times via inspired persons, according to what they were willing to receive and what was best for them (my wording, but see https://www.churchofjesuschrist.org/study/scriptures/bofm/al... ); e) that after Christ's mortal ministry, death, & resurrection, and the deaths of the apostles, that the doctrines were changed by men and worldly philosophies, and the true authority to administer ordinances was lost until being restored (re-established) through Joseph Smith in the early 1800's as part of the preparation for Christ's 2nd coming (see https://newsroom.churchofjesuschrist.org/article/restoration... in various languages or just click English); f) that the Church has the authority to administer the teachings, ordinances, etc today under Christ's direction; and g) that it is the (edit: fix errant paste) only true and living church on the earth today, and guided by living prophets (as Noah, Isaiah, Jeremiah, etc), and apostles. We respect, love, and are engaged in various partnerships and friendships with various religious and humanitarian organizations across the world, and we appreciate all the good done by all who are sincerely trying. (Site also has links on that.)

3) As above, those are not reflecting known, revealed truth from heaven. But, from our Articles of Faith:

"11 We claim the privilege of worshiping Almighty God according to the dictates of our own conscience, and allow all men the same privilege, let them worship how, where, or what they may.

"12 We believe in being subject to kings, presidents, rulers, and magistrates, in obeying, honoring, and sustaining the law."

(https://www.churchofjesuschrist.org/study/scriptures/pgp/a-o...)

4) Each person has to decide for themselves. Many evidences have come to light since the B of M was translated in ~1830, about ancient civilizations (some collections I have linked, and I added an interesting linguistic one to Wkp about uto-aztecan ties to near-eastern languages), but I also read (and believe) statements repeatedly that such will never provide final "proof" either way, but each person needs to ask the Father for themselves, in the way He said (as noted on my site, with references), to get a reliable answer. Such as described in scriptures linked at http://lukecall.net/e-9223372036854743866.html etc.

Also importantly, we believe that everyone will eventually have the opportunity, in this life or the next, to learn truth and receive all that they are or would have been willing to follow, including the essential ordinances, and the opportunity to live in family units forever. That is why we build temples worldwide and do family history work. I believe literally in the Lord's words including "...blessed are all they that mourn, for they shall be comforted." (references linked here: http://lukecall.net/e-9223372036854581793.html )

I hope that helps. There really is a lot more info and means to answer questions if you look. :)