Joseph Smith. He wrote all of the articles of faith.
A signed article identifies the writer whereas an unsigned article does not identify the author.
Article IV, Section I
faith and full credit
The third article from the top!
get yourself in shape and have faith
Generally, no. Once a document has been signed by the parties it cannot be altered by a third party.
if he was a baptized member of the church and he rejected an article of faith, then yes. if he rejected any article of faith without being a baptized member of the church then he is free of heresy.
Article 4
It means we believe in not breaking the law!
Article 4
Article 16 which was signed by the Ottoman Empire, UK and France.
It is not technically an adjective. It is called an article, and is one of the two 'indefinite articles' - the other being "a." The third article is the definite article: "the."