Soon we will kick off the content-submission phase of this project, asking people to prepare questions and answers for publication. We'll make separate meta posts (for different sections) for the prepared questions; this post is to collect candidate links so that (a) we can get a head start and (b) people who don't have time/ability to prepare something can still nominate content.
I'm making this community wiki. Please edit the answer below to link to questions you think would be good. If you can also suggest particular answers and/or the section of the haggadah that it fits in, so much the better. People preparing questions can harvest this list (delete the link here when you do) or do their own searches; no pressure and no guarantees.
Submissions (now closed):
I have locked the above-listed posts to that we can import the content into the final document. Apparently locking removes posts from the main page, which I did not know, but you can get to them all from here.
You're welcome to use any questions you like. If you use one from the list in the answer below, edit the answer to take it off the list.