I think the reason you did not get any response so far is that it's:
(1) unpaid (consider saving up and hiring someone?),
(2) you did not show any progress on the game already made, i.e. it is hard to tell whether this project will ever be completed, and
(3) you kind of make it sound like a competition ("prove you are good enough!") and you list all your requirements etc., but nowhere you list what the other person gets out of it!
If you want to sell the artist on your story, you might have to reveal a bit more so that they can get excited; so that they want to partner up with you for the project. What will make your game interesting? Why should they want to help with it and not, say, make something on their own? What's the unique premise, the message or any other appeal of it?
Which brings me to another point: you need to realize that when you ask for free help, the only doable way to do it is by forming a team, but your post doesn't really reflect that. You need someone who becomes your game-making partner, someone to collaborate with, but the post sounds more like a request for an (unpaid) job.
Also, I noticed you did not credit the art creators in your Dolly game and ask for help finding them. An easy way for you to do it is by reverse-searching the individual images through Google Images.
Good luck with your game!