I like the art of the second artist a lot, even though the first one is the closest. I'd make it work better by having Sonia wear some sort of side split kirtle/cotiehardie with trousers under it. Her dress in the original design is like a super-short version of a burgundian. Maybe something like a cross between a burgundian and a mens' houppelande could be quite cool. The over the knee boots are defintiely feasible in-Period as well, soft leather with lots of buckles to keep them on.