Comic Brief - Illustration Style

I'm still trying to work out whether I should use an illustrative style for the final comic covers or not. The idea is to link it directly to the comic and the comic style by using illustration. The original idea i had was to make 7 volumes for the re-release with a different illustrative cover for each. The idea is something like this:

Each would keep the same kind of style, but vary in illustrative content. I'm still not really sure if the idea is actually interesting enough, the illustrations will have to be fairly detailed to make them interesting as covers and I still can't really tell whether it is a suitable idea or whether I just want to draw pictures. 

I decided each cover could have a different base colour relative to the character it shows. Each character has attributes which give them different kinds of colours, so this wasn't too hard to think of (click to enlarge):

To see if this was at all appropriate, I took the thumbnail of 'Death' above and really quickly applied the same styles that I used with the original 'Dream' illustration to see how they might work as a set. 

I don't think I'm really happy with the style of this as a final idea. The black and white is too simple and it makes the whole thing kind of uninteresting in general, as well as not being that relevant to the colourful comics.