I like all your dolls, so it shouldn't be difficult. xD
I had two ideas for how it could work; the laws of physics have the day off, so the characters can do things like break blocks with ease and carry around massive amounts in their inventory.
Also, the plot would be much easier than you think. A city full of builders beset by griefers, for example. Because while the real world wouldn't exist, things like griefers would. xD Or perhaps a quest to find and activate an End portal, and then defeat the Enderdragon.
It strikes me as fun because I'd get to twist the rules of reality and stuff. The only seriously difficult question that strikes me is whether or not the characters should be real-real, or just old-looking models with a low polygon count. Apart from that, I've figured most of it out.