It's not a coincidence. The guitarist's father admired scouting and Baden-Powell. So that's how he got the name.
The guitarist's full name was actually Baden Powell de Aquino. He did pronounce it a bit differently, however: BAH-den instead of BAY-den.
More Brazilian music:
Tania Maria with Boto and Helio - Via Brasil (Barclay FR, 1975)
Sunnyside CD reissue