Close them as duplicates of the first linked question
In general, almost all of those last set of questions seem like different subsets of a question asking "What abilities work in an antimagic field?" However, that question itself seems to be a duplicate of the very first question you linked: How do I know if an ability is magical?
The very purpose of ...
This question seems reasonably confined to be answerable
Sometimes the following automated message appears when asking a question:
The question you're asking appears subjective and is likely to be closed
Remember that this is automated, and isn't going to know everything best (though neither will people). At least for me, I have found that the automated ...
It is on topic
However, whether the community will think your question is good or not (which will be reflected in the votes) is highly dependent on how you present the question. Good formatting, wording, and clarity play a big role.
Then there is 'research effort'. Back then Stackoverflow was originally built to be an experts site, so the system was ...
In my opinion, it's going to come down to wording and whether the community feels like the querent spent more than 2 minutes thinking about the topic.
Anecdotally, I feel like some questions get negative reactions because they're written like an anxious child: "hey guys, I had an idea and was wondering what all of the ways to be good with a sword ...
I would say reopen #1 and leave #2 and #3 as is. I believe you were correct with your interpretation as mentioned in the "rereading" paragraph. However #3 is attempting to clarify if the damage from AoA is only valid with the THP granted by AoA or if it works with any THP.