Hi Sheilagh! What an interesting question! I'm Cuban so it'll be easy to answer it. We Cubans do understand "hola" but we barely use it. Instead, we have a very very common phrase that is "Qué bolá!?" which I would dare to translate it as "what's up!?" But this is, say, something young people say... My parents would say "buenos días" and stuff like that. There is another version of "Qué bolá" that goes like "Qué vuelta!?". There are many other ways to say hi in Cuban slang just those two are very common. About "mijo/a" we do use it, sometimes we change it for "mio/a" PS: VERY IMPORTANT, "Qué bolá" is only followed​ by another "Qué bolá" or maybe by a "Qué bolón" don't you ever say "bien", "mal", etc hahaha common mistake.