The singer's son died Thursday after reportedly having issues with breathing.
The punk band's co-founder retired from performing in 2015 due to health issues.
The Nashville-based Cooper died Tuesday after a fall.
S-Curve Records CEO Steve Greenberg, who worked with Stewart on "The Complete Stax/Volt Singles 1959-1968," remembers the pioneer and his groundbreaking label.
Marvin Gaye's 1977 disco single “Got to Give It Up,” which reached No. 1 on the Billboard Hot 100, featured Jan on background vocals.
The late label chief is "an important piece of American music history," and an instigator in the Southern soul movement.
Alley died of cancer that was only recently discovered, her children True and Lillie Parker said in a post on Twitter.
He performed on 'Sing Along With Mitch' and was a teenage idol in Japan before spending 46 years on the iconic kids TV program.
The 'Phantom of the Opera' touring lead revealed earlier this year that he was diagnosed with stage 4 colon cancer.
No cause of death has been revealed.
