"The only thing they copied" are face, pose, whole concept, which basically means the entire artwork already. And it's not just "copied", it's tracing, and tracing is considered art thief. It's not about whether or not you have problem with this, this is wrong, especially when it's an entry to a contest where monetary prize (or similar to monetary) is involved.
I have tried to raise this issue on reddit (though by now I assume no one read things there), reach the community team via the official twitter (no answer whatsoever) and after I wrote an email to support they tell me to post it on the forum, so here I am, with a question direct to the community team, and I hope to receive a clear answer. (I'm just gonna quote my email here)