Pupkin

Everyone calls Wirman by his last name, like. Not a single person doesn't call him Wirman. Even Dirk. It's probably a mix of him being a somewhat famous author and being kind of closed off.

Nearly everyone (except Zephyr and maybe Symmetry) calls Dirk by his first name. He's just plain Dirk. Likely because he's a very open and informal kind of person.

Basically everyone calls Madam Tadpole 'Madam tadpole' or just 'Tadpole' except for Magnus Mortuga who calls her Tanya, indicative of their closeness. Despite them knowing eachother Mariana moon does not do this, or at least not to other people's faces, a nice way to convey that their relationship is familliar but not too familliar I think.

Most people refer to Magnus Mortuga as either 'Captain Mortuga' or simply 'Mortuga'. Tadpole refers to Mortuga as Magnus in same vein as he calls her Tanya, and so does Zephyr, but a neat detail is that while Gripp calls Zephyr 'Zacharias' and Zephyr calls him 'Godrik' (because they've known eachother a good while)

very interestingly, Gripp only rarely if not never calls Mortuga just plain 'Magnus', at least not to our faces.

We know from the end of the game that Mortuga did also call him 'Godrik', so it's just Gripp doing this weird avoidant formality for Mortuga in specific, and it's not purely to avoid suspicion because I'm fairly certain he keeps doing it even when you've already caught him. It feels like it's either his buried resentment showing, or it's a way to distance himself from his own actions by not acknowledging any level of kinship or familliarity they might have had.

Gripp also just. Generally calls most people by their first names (except for like Wirman who no one calls by his first name and Madam Tadpole which I think is mostly because he doesn't know her full name). Which just makes how he refers to Mortuga stand out more to me.

Sinthia is generally either referred to by her first name or 'Miss Seafoam', but practically no one? calls her Captain Seafoam the way they do Mortuga, I think emphasizing just how hollow her reclaiming of the submarine is. It makes me feel a little sad for her but to be fair it also takes longer than a day to adjust to new leadership so I don't think it's a lack of acknowledgement alone.