Hello,
I would just concentrate on the "Non" www site as it is the one that has the content. If you are redirecting traffic from the other site it will be ok, but don't post any additional links to the "WWW" site though. Also like you said it would be a good idea to go back and correct the links if there are not too many of them.
You don't lose much from the redirect, but the "Dampening" factor of PageRank does deduct a small portion of the links value.
In reality, if the "WWW" site is not being used and has no content just make sure it permanently redirects to your main site and forget about it. Put all your effort into your main site. Build lots of high-quality content and promote it. It takes a little time for the links to start showing up in MOZ, but when they do it can start building fast. Then your "DA" score will start going up.
You may like this article regarding "Organic Quality Scores" and I hope it helps you.
Best Regards