The name Omar عمر is a pre-Islamic male proper name. Several of the Prophet's companions were called Omar, the most prominent of which is the second successor to him, Omar Ibn Al Khattab.
In Latin America, the name is popular in the 20th century. For example, we have Omar Sivori from Argentina, Arthur Omar from Brazil, Omar Jose Daal from Venezuela, Omar Cabezas from Nicaragua, Omar Rodriguez Lopez from Puerto Rico, and Omar Romano from Mexico.
Although Moorish influence through Spain is a possibility, it is hard for me to accept that this is the case. No 16th or 17th Spaniard Or Portuguese would like to be associated with a Muslim/Arab name, not to mention that the Inquisition would not approve of this, let alone social norms.
As we move north to the USA, we find that a few African Americans also use the name Omar, such as Omar Gooding, Cuba Gooding Jr. brother, as well as Omar Epps. This is not that surprising knowing that African Americans do use Muslim and Arab names, whether they themselves are Muslim or not.
However, that extends to even white Americans, such as Omar Knedlik, the Kansas City inventor of the ICEE, later to become the 7-Eleven Slurpee.
The most famous white American who went by the name of Omar, is Omar Nelson Bradley, General of the Army of the United States. The M2 and M3 vehicles are named Bradley after him.Now, how would a late 19th century Christian white American gotten the name Omar?
Puzzling, isn't it?