When you say there is no activity, how are you trying to see if there is activity? It is very unlikely for example that the plastic bag with holes would inflate.
As for smell, you'll always get funny smells in fermenting beer. My worry is fermenting in the cube and playing with it so much
Not sure how you are going to get a sample out of the cube but try and do so as cleanly as you can and let us know what you discover.