Hello alix, i am still pretty a new to vvvv (only did three pwojects by now), but already had experience with both parts of your question so i would like to share this experience. Using Kinect is very easy in vvvv, but I believe you need to use an particular old version of the kinect (this i was teached in a workshop around five years ago, so someone correct me). Once you have the Kinect connected its just numbers like everything else so you can do what you want.
For the AE Part have a look at the video documentation of one of my projects. In the video you can see the vvvv patch, the AE workflow and the final video installation:
I used AE to render multiple layers and then put them in vvvv together again by using blending modes. As input I used Megnetic Field Sensors connected to an Arduino and used this Input to blend between layers.
Of course you could also put some vvvv realtime effects over your particular layers so in the end no one can say – is it vvvv or After Effects or what :-)
I hope I could help you to find the right decision ;-)