Pflanz takes over as deputy chair from Berndt-Michael Winter.
Paul Ross will make way in July, prompting the two moves.
Rigby was previously head of strategy at Don Papa Rum.
The pair are set to start their new jobs this week.
Huub van Doorne will give way to Frank Cocx later this year.
Decaux has moved across from rival Terroirs et Vignerons de Champagne.
Mauricio Vergara left Bacardi after 12 years in December.
Southern Glazer's has partnered with Campari Group for around 35 years.
Sengara's tequila experience includes two years with Combs Wine & Spirits.
