Very little is known about the route Lehi and his family took. We can generally understand that the Nephites and Lamanites landed in South America and dwelt in South and Central America.
Would the Lord ever direct one person to kill another, as in the case of Nephi being ordered to cut off the head of Laban?
Accounts are not uncommon in the scriptures where the Lord uses his servants to destroy the wicked in order to accomplish his righteous purposes.
Mormon Church leader Joseph Smith did see the sword of Laban in the Hill Cumorah and it was one of the relics given to him with the golden plates.
Intelligences are eternal entities from which all living things are created. Intelligences cannot be created, they have always existed.