Were both Dave Pirner and Aaron Pauley lead vocalists at some point in their music careers?
yes
Title: Aaron Pauley
Passage: Aaron Pauley (born August 4, 1988) is an American musician, singer, songwriter, and bassist born in Vacaville, California.  He is most prominently known as the lead vocalist and bassist for the American heavy metal band Of Mice & Men.  He formerly was the lead vocalist in the bands Jamie's Elsewhere and Razing Alexandria.
Title: Dave Pirner
Passage: David Anthony "Dave" Pirner (born April 16, 1964) is an American songwriter, singer, and producer best known as the lead vocalist and frontman for the alternative rock band Soul Asylum.
Title: Jason Karaban
Passage: Jason Karaban is an American singer-songwriter and musician living in Los Angeles, California.  Karaban first began his career fronting the Philadelphia-based indie rock band "Dragstrip Courage" in 1997, and "Grand" in 2000.  He emerged as a solo artist with the release of "Doomed to Make Choices", in 2006, co-produced with Mike Napolitano (Joseph Arthur, The Twilight Singers).  Along with vocals, Karaban plays acoustic guitar, 12-string and electric guitar, bass guitar, keyboards, piano and drums.  Karaban has released four critically acclaimed albums, and has had a number of songs featured in film and television shows Over the course of his career, Karaban has collaborated with many notable musicians including Ani DiFranco, Lucy Schwartz, Sara Watkins and Sean Watkins (Nickel Creek), Garrison Starr, Taylor Momsen, Dave Pirner (Soul Asylum), Glen Phillips (Toad the Wet Sprocket) and Benmont Tench (Tom Petty and The Heartbreakers).
Dave Pirner Aaron Pauley