The Almoravids are just one part of the Moors. There were the Almohads.,Almoravids, Abbassids,and Ommayads who took control of Spain. But many of the Almoravids were from North Africa who had already been stamped out with Roman ,Turkish and white Berber descendants. Not to mention the Ommyads were a group of people that stretched from modern day Morocco,Algeria, Tunisia, Palestine ,Syria, Iraq and the Arabian peninsula. The Ummayads were universal dynasty who beleved that Umar and the descendants should be the Caliphate
A few would mean not more than most in the post. Children of concubines does not signify legitimate lineage to the fathers and of an ethnic groups. Concubines also came from Turkey .Albania and all over.
Arabs had alot of slaves from all over I don't get your point, Slave were even people of Eastern European descent, henceforth the name Slavs.The fact that they imported slaves into North Africa even tells you the disconnect these Arabs had with the local African people,which had the blackness breded out of them by this time.