Responses

I think if you've watched the anime that's fine, you'll understand/enjoy the mangas, since you know who is who.
As for which order you should read the mangas in, since they're supplementary materials I don't think it really matters. Just avoid reading the More Blood ones, until you've watched that season too. I think More Blood has new characters
I want to read Diabolik Lovers manga. What order should I read them?