Most of Giuseppe Verdi's operas were published by Casa Ricordi, a prominent music publishing company based in Milan, Italy. Casa Ricordi played a significant role in promoting Verdi's works and supporting his career as a composer.
none they were all its'
No. Operas have been written in virtually every language.
The scores and parts of Puccini's operas are all in the public domain.
In operas the people on stage sing their words instead of saying or speaking them.
Opera singers all sing all kinds of operas. There are no special terms for singers of comic operas.
The second one. Traditionally, operas have little or no spoken dialogue at all - as opposed to musicals, which have songs to illustrate major sequences and dialogue in between. (Thus Lloyd Webber's "Phantom", insofar as the film, is NOT actually a traditional opera, nor is the stage show; it is technically a musical.)
One can find information regarding operas in Australia at the official Sydney Opera House website. One would find all the information they require about operas.
go puck yourself
Operas have been written in most all languages on Earth, primarily the European, Asian and English languages.
Wagner
Impossible to answer as it is totally subjective and covers all types of operas - but it is usually accepted that the most popular operas are Carmen and La boheme.
In the USA Tide, Cheer, and All are the top three sellers as they have been for about 5 decades. They are the ones who made "soap operas" to be called soap operas.