h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I'm the Rev. Donald Hoff, living in New York State, USA. Recently I discovered in a search of my family history, that my Great Great grandfather , Giovanni Domenico Mariani, born (1805)in or near Milan, Italy, was a violinist at La Scala for 20 years. He came to Havana, Cuba with an Italian Opera company, around 1840, and was there with Antonio Meucci (inventor of telephone) and Guiseppi Garibaldi (the Liberator), then come to the USA and worked with them in 1850-1880's. He was a musician with the opera in NYC and Boston.

I know that he lived up to at least 1886. I don't know anything about his time at La Scala, nor when he died, nor where he is buried. Perhaps it is in Italy. I suspect that he was a very political person, and he was likely to be engaged in the liberation of Italy.

I know that he was a close pesoanl friend of Garibaldi, and testified at the law suit of Meucci against Bell Telephone company in 1885-1887. These gentlemen lived in Staten Island, NY, where there is a museum.

How can I find out more information about him? What might be available in the history of La Scala? Is he related to any of the other persons at La Scala named Mariani? Resources here, so far, don't provide anything. Does anyone have any information or ideas.

Thanking you in advance.