There are other ways to draw attention to your question. Editing it is the primary way. Add more information about what you've found out. For instance, you can add that you tried that thing and you thought it worked at first but it didn't.

Not without involving developers, and this generally isn't done unless there are privacy or legal reasons to destroy the post.

Hover your mouse over the star, and wait a moment.

And people think I'm paranoid for blocking ads.

We have about 27,000 of 156,000 questions showing as unanswered. I've spot checked some of these before; it's my opinion that most of them have an answer worthy of being upvoted, or the question just needs to be closed.

I don't think this can easily be done in a user script; it would hit the API very hard and as a result run very slowly. Then it would get rate limited and fail...

Doesn't really matter to me....