1. If I did not intend to refer to the plaintiff in my article, and it was a pure coincidence that the article appears to refer to him, will I still be liable for defamation?
At common law, it is immaterial that the defendant did not intend to refer to the plaintiff, or did not even know of his existence. According to Gatley on Libel and Slander [10th edition], the test is "would the words complained of be understood by reasonable people who knew the plaintiff to refer to him?" If so, the words complained of are published about and concerning the plaintiff, no matter what intention the defendant may have had.
If you are being sued for defamation, you cannot make a successful defence by showing that you did not intend to defame the plaintiff when in fact you have done so.
In a British case, the defendant published an article defaming a named person believed by the author and the editor to be a fictitious person with an unusual name. The name was in fact that of the plaintiff, a barrister in practice. Neither the author nor the editor of the article intended to refer to the plaintiff. They even swore that they did not know of his existence. The judge had directed the jury to decide the case on the facts, not the intentions of the defendant. If the jury thought that any reasonable people reading the article would think it referred only to a fictitious person, then the article could not be considered defamatory. However, if the jury thought that reasonable persons who knew of the existence of the plaintiff would think that it referred to him, the jury ought to find for the plaintiff (i.e. the defendant is liable for defamation) and it was immaterial whether the article was intended by the author or the editor to refer to the plaintiff or not.