Gonzo is a supporting character from Jim Henson's Muppets franchise. He is a loveable, long-nosed...purple...thing with a passion for performance art and stunts. Although he's friends with all of the Muppets, there's a special place in his heart for Camilla.
For the majority of Gonzo's appearances, Dave Goelz performed him. As with literally every single Muppet character, Dave created an instantly recognizable physical and vocal performance, embuing Gonzo with zany mannerisms and a raspy voice.
Russi Taylor voiced the baby version of Gonzo in the 1980s animated series. Russi does very well at creating a voice that is noticeably young, but also distinctly Gonzo.
For the 2018 Muppet Babies series, Ben Diskin stepped behind the mic. Ben's Gonzo is different enough from Russi's, yet still believable as being a young Gonzo.
Dave gets my vote, but both Russi and Ben are perfect fits for the young version.
*Once again, a big thanks to BTVA'er Ghosty404 for the clips!