Who, then, was the first person to document or offer the "captain's daughter" lyric?

It would be good to know whether that version, in its other lyrics, maintained the "punishment" theme -- as in real punishments (not the "shave his belly" cutesy ones). If it is a post 1950s lyric, then we really need not look for any obscure or metaphorical meaning for "captain's daughter."

OTOH "What shall we do with the captain's daughter?" sounds like a good possibility wherein, instead of enumerating punishments for the drunken sailor, the theme would be to say "What shall we do with X?" , "with Y" "with Z" etc. Another possibility is that *that* was traditional, and that in the cutesy/parody remakes it got changed to "in bed."

Both Colcord and Masefield say that "Drunken Sailor" was sung in chorus throughout. (Though I'd like to leave open the possibility that Colcord is echoing Masefield's description, not that they necessarily corroborate one another.) Did they truly mean throughout ALL the song? Hugill, for example, has it where the thrice repetition of a line is sung as solo. And many singers interpret it still another way, where a soloist sings out the line first (as if to let the others know what the lines is to be), and is then joined by chorus on the repetitions. This would make a difference as to how we understand the text, because the last two ways of doing it allow for improvisation/creation, whereas the "in chorus throughout" method suggests that everyone would know in advance what was to be sung, and therefore a customary set of verses would have been well established.