What honorifics might young adults use for friends in differing contexts?
I'm a writer, and part of a story I'm writing involves a supporting character who is japanese and I would like her to use typical honorifics for her friends, but I have very limited knowledge of japanese and certainly do not have a nuanced understanding of how honorifics are used for different ages and genders, especially in contexts such as speaking among friends or in the presence of an authority figure. Would a character use "-san" when speaking to a stranger about their close friend, or would they use a more familiar honorific? Would it depend on the personality and manners of the speaker? I also have read on a few different japanese-learning websites that a person may nickname friends by shortening their name before adding the honorific to the end (for example, shortening Masahiro-chan to Macchan), is this true?
Please let me know if the question is confusing, and thank you for your help.