Topic Ratings Plugin

Yes that’s all doable. I haven’t been doing a lot of work on the QnA plugin, so if you want to use that in a serious way you’ll need to take a close look at it and test its functionality thoroughly.

Not entirely sure what you mean here, but this would seem to be something your moderators would handle, at least initially.

Sounds a bit like you may want to also use Topic List Previews.