I am pretty certain that mi (nom. sg. masc.) is the only one that differs from the nominative, hopefully someone else will chime in and verify. All other genders, singular and plural, have the same form as the nominative including noster and the rest.
confirmed, meus is the only one with a special vocative. note that ‘mi’ is only vocative singular masculine, the other genders are normal and the plural masculine is ‘mei’. Also, consider that possessive pronouns would not normally occur in the vocative except in the first person (and usually first person singular, at that).
Salve Swth\r
“Meus” is rarely used in the vocative, but it can be. “Mi” is regularly used. Non falsum est, sed rarò vocativo casu utitur. “Mi” plerumque utitur
meus is used for the vocative in certain cases for stylistic reasons. For instance, deus has a base of “de” and so uses deus as the vocative (as opposed to ‘dee’) and so throughout the Vulgate you will find Deus meus “my God!” and not Deus mi, which would technically be correct although not preferred. So, meus fili is not technically wrong, but mi fili is much better.