1.The answer is a parody on the letter of Mehmet II who presents himself variously as an overlord or the king of Macedonia.

2.Dmytro Yavornytsky suggested wheelwright (kolesnik) was slang for someone who speak overwrought nonsense (okolesica) rather than one who makes wheels (koleso).

3.There are more than 10 different manuscript copies and there are a lot of squabbles about the original text and the original language of the letter (and whether it existed at all or was fabricated as propaganda). There is a copy in pure Moscow Russian stating it is a translation from Polish. There are manuscripts suggesting it was poorly copied from one of the dialects of what would later become Ukrainian. It's all wonderful fodder for nationalist squabbles and each scholar party has good arguments in support of their cause.