Yes. This is a proper noun as any country name.
Yes, you always capitalize "Cuban."
You would never capitalize a word because of the comma. Onlt capitalize it if it's a word that is always capitalized like France, I, Tuesday or Frederick.
Yes, always.
No you do not.
Yes, you capitalize Spanish because it is a language and culture.
Yes, you always capitalize a day of the week.
Yes, always capitalize a state.
Yes, you should always capitalize a proper adjective.
Always. It is a proper noun.
no
Nope!
Euro is always capitalized.