It was not argument but, screenshots of historic book written by Yemeni writer in Middle age. in the book (conquest of Abyssinia) he mentioned the names of Somali tribes that fought and ruled Adal.No translation needed. What you have here is only part of the argument and does not satisfy the matter:
"Imam Ahmad is regarded by many scholars as an ethnic Somali. However, other historians have disputed his ethnicity, with Ahmad sometimes interpreted as being a Harari  Many Somali clans played a strong role in Gurey's conquest of Abyssinia, however these clans went to war not so much as Somalis but as Muslims."["
There is no agreement on this because his ethnicity is unknown. Everybody claims him but nobody has definitive proof. The Futuh itself does not cover it. In addition to Harari, others have asserted he could also have been Arab or Afar. Note the religious, non-ethnic, basis of the war.
You still haven't supplied a link.