Complex sentence: Anastasio's "de facto" leadership being duly noted, the other members of Phish played important roles in the band's persona and overall sound, and they have each had successful music careers outside of Phish.
Split into simpler sentences: Anastasio's "de facto" leadership being duly noted, the other members of Phish were far from merely supporting personnel. Each played a unique and indispensable role in the band's persona and overall sound, and they have each enjoyed successful music careers outside of Phish.