If your quiz has been in the queue for what you feel is a very long time, first thing to do is to check that it actually was submitted. I can't tell you how many "My quiz has been waiting two months" letters I've gotten, about quizzes that were never resubmitted. When you go to the "my quizzes, edit" page, you can see the quiz status. If it has been submitted, please don't send a note. We'll get to it when we can - it won't be forgotten.
As for the first question. Personally, I appreciate a heads up so I can look out for it, if there has been quite a bit of discussion. If, say, we had decided to have a go at a quiz in a closed category, and the author had sent sample questions to me already. If the discussion was just something like "Can I write a 20 question quiz in this category?" or something else fairly minor, I wouldn't think a note would be appropriate. We are getting to your quizzes as fast as we can, and if it's in the queue, it will get looked at.