Is death an extinction?
In the sense of the particular body, certainly. In the sense of the whole person probably not. That person has influenced others and for better or for worse that person will be remembered by those influenced. "Visiting the iniquity of the fathers upon the children unto the third and fourth generation of them." Actually God is a piker. The iniquity of some is visited on human memories for millennia, if only in myth.
On the other side of the moral ledger those that have enriched human culture will be remembered as long a people can make music and tell stories. Homer, Jesus, Shakespeare, Palestrina, Mozart and countless others are long since returned to the stardust of their origins. To say they are extinct is the raving of a fool. One can easily understand that the kid that sang "Twinkle, twinkle little star" or more likely "Ah vous dirai-je