Hello tando, sorry for the late reply. I was waiting for some new information from my aunts in Taiwan about the 戶口名簿, and wanted to reply to both topics after I got new information.
Anyway, the person who originally told me that AF384 does not require active household registration also mentioned the thing about 除戶謄本. He said that the bureau will accept a 除戶謄本 for the TARC application for those cases where the parents do not have active household registration anymore, and told me that I should just go to any office with my mother’s old (expired) 戶籍謄本, and ask for my mother’s 除戶謄本.
What makes me wonder though: Even if the 除戶謄本 can be regarded as a form of 戶籍謄本, the required documents for AF384 do not mention a 戶籍謄本 but only a 戶口名簿. It is AF353 (where you need active household registration) that allows both 戶口名簿 and 戶籍謄本 (and would therefore also allow a 除戶謄本 if we say, in logical terms: a 除戶謄本 IS A 戶籍謄本).
From what I’ve found so far, the statement 除戶謄本 IS A 戶口名簿 cannot be made (yet). It would be nice to find a resource similar to “for applicants who cannot provide a 戶口名簿, a 戶口名簿 == 除戶謄本 equality can be made.”
The confusing thing is why AF384 – which does not require active household registration – requires a document (戶口名簿) that is seemingly harder to get if your parents don’t have an active household registration anymore. At least this is my impression about the 戶口名簿, because all of my aunts told me something like “Don’t know where we have old 戶口名簿, they often get replaced by new one’s and they always look different than the last ones,” etc.
I’m therefore still waiting for them to find an old 戶口名簿 with my mother’s name on it.
EDIT
To make matters even more confusing: I once briefly mentioned that there are 2 “適用對象” options: One that requires active household registration (有直系血親、配偶、兄弟姊妹或配偶 之父母 現在在 臺灣 地區設 有 戶籍) and one that doesn’t (居住臺灣地區設有戶籍國民在國外出 生之子 女,年 齡在 二十歲 以 上). However, interestingly, in the “身分” document, the AF353 option (which allows 戶籍藤本) lacks the 現在 requirement: 有直系血親在臺灣地區設有戶籍者。
However, it says for applicants that we born overseas, the required document match with those of AF384 (以居住臺灣地區設有戶籍國民 在國外出生之子女身分申請 者,證明文件同AF384), thus excluding 戶籍謄本 again by that logic.