Historical clue formulations

• One-named performer known as "Mr. Showmanship" — 2025-12-31
• Subject of HBO's 2013 biopic "Behind the Candelabra" — 2023-02-21
• Showbiz's "Mr. Showmanship" — 2020-12-26
• Longtime Las Vegas entertainer — 2012-08-30
• Owner of the vanity plate "88 KEYS" — 2006-02-02
• Entertainer born in May 1919, the basis for five anagrams in this puzzle — 1999-05-26
• Entertainer whose given names were Wladziu Valentino — 1997-02-01