Does the selection of names for newborns and the determination of marital compatibility, based on a method followed by a saint (whom the father describes as a polytheist, yet he is convinced of the accuracy of his process), and who asserts that it is based on the hadiths of changing names in Sahih al-Bukhari, and given that the father believes his name—which he chose randomly—has caused him problems, and this saint believes that to rectify this, he must choose a name for his son beginning with the letter "M," have any basis in Islamic law?

The fundamental principle regarding names is permissibility, unless there is something that necessitates prohibition or disfavor. Therefore, there is no need to consult scholars regarding naming unless the name's meaning is unknown. The name "Omar" is good. What is said about it causing problems is false talk and blameworthy divination, which is forbidden in Islamic law. It is a form of quackery and sorcery. There is nothing in Islamic law that specifies a baby's name must begin with a certain letter.

If you are blessed with a newborn, give him a good name. The most beloved names to Allah are "Abdullah" and "Abdul Rahman," or the names of prophets and companions. It is advisable to avoid compound names consisting of several names, such as "Muhammad Shams," because they were not part of the practice of the righteous predecessors and can cause confusion.