Citing three households in one citation

Hello, keepingup. By punctuation rules, commas separate like items in a series. When some items are alike and some items modify other items, clarity calls for a different form of punctuation for the modifiers. Normally, by punctuation rules, when we have several items in a series and some of those have a need for internal commas, we would use semicolons to separate the major items as you suggest. However, in this case, we're already using semicolons to separate more-major parts of the sentence.

What EE would do in this case is use parentheses around the modifiers of the three items in a series (i.e., the householder identities):

1830 U.S. census, Maury County, Tennessee, p. 392 (inked), line 9 (Marine Duvall household), line 10 (Benjamin Duvall household), line 14 (Andrew Duncan household); image, Ancestry (https://www.ancestry.com/discoveryui-content/view/720829:8058 : accessed 21 March 2022); citing NARA microfilm publication M19, roll 177.

You'll also note that I placed the phrase (inked) in parentheses also, rather than the square editorial brackets. We use editorial brackets when we, as editor, are making alterations in a document or in someone else's writing. In the creation of this citation, you are the writer, not an editor. You are writing a citation sentence in which you report details. If you were to quote something in your citation, with quotation marks around it, and you were to change a word, then square editorial brackets would be appropriate because you would be altering someone else's words. But in this case, you are using your own words to identify the record.