Short answers, pulled from the story.
Zeno, born Tarasicodissa Rousombladadiotes in Isauria, ruled as co-emperor starting on the 29th of January 474 and became sole ruler after Leo II died later that year. He reigned from 476 to 491 following a brief usurpation by Basiliscus.
Zeno died on the 9th of April 491 after ruling for 17 years and 2 months. Sources suggest he succumbed to dysentery or epilepsy rather than the false tale of being buried alive.
In 482, Zeno issued the Henotikon, also known as the Act of Union, to mediate between Chalcedonian and Miaphysite views about Christ. The edict affirmed the Nicene-Constantinopolitan Creed while excluding other symbols and condemning Eutyches and Nestorius.
Zeno played the two Ostrogothic leaders off against each other to prevent attacks on Constantinople. In 476 or 477, he allied with Theoderic the Amal to attack Strabo, eventually allowing Strabo to receive wealth before Strabo died in an accident in 480 or 481.
Ariadne chose Anastasius, a favored member of the Imperial court, to succeed Zeno after his death on the 9th of April 491. No sons were available since Leo had died in 474 and Zenon died in youth at court.