If you're talking about only the women, they're Fältskog and Lyngstad. But if you add the males, they're Ulvaeus and Andersson.
fogelberg
The Visitors.
See link below for ABBA discography.
American folk singers, the Beatles and Elvis Presley.
Oh, dude, singers with last names ending in "o"? Let me think... how about J.Lo? Yeah, Jennifer Lopez counts, right? And there's also Pitbull, if you're into that. But honestly, who even pays attention to last names these days? Just enjoy the music, man.
abba
Anni-Frid Lyngstad Björn Ulvaeus Benny Andersson Agnetha Fältskog If you read the first letter in each name it reads ABBA:)
fogelberg
Presumably when they were born. If you mean the band itself, they adopted the name (acronym) ABBA in the summer of 1972, two years after they started performing together. (Before that they just used their first names, Bjorn & Benny, Agnetha & Frida).
The Visitors.
fontella bass ed ames
Usher Uncle Cracker
See link below for ABBA discography.
a-ha abba Gregory abbott ac/dc
American folk singers, the Beatles and Elvis Presley.
Mary J. Blige Toni Braxton
Oh, dude, singers with last names ending in "o"? Let me think... how about J.Lo? Yeah, Jennifer Lopez counts, right? And there's also Pitbull, if you're into that. But honestly, who even pays attention to last names these days? Just enjoy the music, man.