Sultan as-Sayyid Sharif Osman ibnu Sultan 'Abdu'l Rahman al-Qadri (r. 1819-1855) had 22 children, amongst whom was his second son Sharif 'Abdu'llah. I do not know about his nickname but his daughter married Sultan Sultan as-Sayyid Sharif Yusuf ibnu Sultan 'Abdu'l Hamid al-Qadri (r. 1872-1895). Unfortunately, I do not hae any information on any other children that he may have had but would be very interested to know about your family.
The settlement of Kubu, by Arbas from the Hadramaut, in Yemen, was affected in 1720. However, the state was not founded until 1772, by Sharif Idrus.