All of the claims that NREM sleep is less vivid or about certain things seem to be inaccurate, as the research I've managed to come across all seem to have different ideas- some say that NREM is less vivid, others say just-as-if-not-more vivid, while some say NREM is about daily drudgery while others say NREM is just as fantastical as REM, some say NREM is more 'abstract', while others say it is identical to REM in 'form'... Unless the individual subjects themselves have their own different types of NREM (ex: in John NREM will not be vivid and will be 'realistic', while Jane will have highly vivid and fantastic NREM) what I've essentially taken away from it is that there are no strict rules and that the average dreamer is not going to be able to tell NREM from REM dreams because the experiences, on average, seem to be the same.

Yes, you can dream in NREM.
Yes, you can lucid dream in NREM.
Both of these have evidence supporting them, you can easily find articles on the subject.

You may have trouble WILDing straight into an NREM period. I am not an accomplished WILDer in the slightest, but from the literature I've read as well as the personal accounts in DV, it is POSSIBLE. However, since it is the very beginning of your sleep cycle, you may have trouble doing it and it's probably not recommended for those who are not adept at WILDs. It is possible, though.