Cool I love this sytle too, ok so there are illustrations of public domain. Yes I see your icons for your Character classes are different indeed.
Since the illustrations inspired me, I make a test :
Not perfect for shure, I keep appearance of the knight by giving it a new position. The downside is, that I've strayed a bit from the 13th-century illustration style, but it was to see what a sprite rendering would look like. What do you think? Anyway, I'll read your rules when I can, probably see ya!