While often used to indicate an error, the Latin adverb sic meaning "thus" (shortened from sic erat scriptum, "thus was it written") simply means the quoted material has been written exactly as in the source. It is often used to indicate that an apparent error, or archaic or nonstandard language, was in the original text and not introduced by the current author.
It is also sometimes used intentionally in an ironic or derisive tone:
Sic may also be used derisively by the proofreader, to call attention to the original writer's spelling mistakes or erroneous logic, or to show general disapproval or dislike of the material (Wikipedia).
The closest "sibling" to sic in English usage would be the Latin adverb recte, meaning "rightly," which is used to correct an error in addition to pointing it out:
"I explained it, but it went right over there [recte their] heads."
Other Latin words and phrases are used in parenthetical remarks with specific uses in English, generally written as abbreviations:
- n.b. (nota bene, "take note")
- d.m. (dignum memoria, "worth remembering")
- e.g. (exempli gratia, "for example")
- i.e. (id est, "that is")
- ca. or c. (circa, "around" or "about," particularly for dates)
- viz. (videlicet, "namely")
- sc. (scilicet, "that is to say")
- cf. (conferre, "compare")
- ibid. (ibidium, "in the same place")
- q.v. (quod vide, "which see," to direct the reader to more information)
- s.v. (sub verbo, "under the word," used in dictionaries or indices)
Other citation signals are used commonly in legal and academic texts with a combination of English and Latin words.
You will also sometimes see parenthetical punctuation to show an author's reaction to a line or quotation: Jim casually walked up, dripping wet. "I drove my car into the lake (?!) and decided it was a nice day for a swim."
For the other specific uses you mention, a bracketed comment with a clear explanation, perhaps coupled with one of the above abbreviations, should be enough to get your point across.