Q: "Baron, a childhood friend of the composer..."

The dates in their biographies are a little sketchy but... Lionel Belasco arrived in New York c.1914 at the age of 33. No mention of prior trips to Canada, France or the American west coast.

Maurice Baron was born in France, moved to Canada and left the family farm c.1906 to join the circus as a clarinetist, age 17. He settled down in New York in 1919 as house conductor of the Roxy Symphony, age 30. No mention of circus routes to the Caribbean but it's certainly possible.

I can't place them together until 1943's notorious songbook but both were probably adult, working professionals whenever it was they first met.

It does seem like Maurice Baron was in the San Francisco Symphony and Mare Island Navy Base bands at roughly the same time as jazz bandleader Paul Whiteman, both on viola.

Probably coincidental but, Edward Colby, adopted son of Charles E. Colby, was also a Mare Island bandleader at the exact same time and Colby the Elder died in San Francisco in 1913. Thirty years later Baron and Belasco would publish Louis Camille (a Colby variant) in that same calypso songbook.