I wish when I had created the Place your lenticular (S0) galaxies in this thread
thread, I had been able to give some concrete morphological criteria for identifying these magnificent objects. But unfortunately, the morphology of these galaxies is very complex and varied. You have instantiations of the "classic" S0 galaxy, with the compact and bright nucleus embedded at the center of a featureless, smooth disk. But then, you have lenticular galaxies that have inner and/or outer lenses, inner and/or outer rings, bars and even remnant spiral structure.
At this time, we do not really know exactly how these galaxies came into being. With that said, let me state that I firmly believe that some spiral and ringed galaxies are the progenitors of S0 galaxies. But, I do not, at this time, have enough evidence to firmly scientifically establish this belief.
From what I have seen, though, of the lenticular (S0) galaxies thread, it seems to me that overall most GalaxyZoo members have a good grasp of what to look for when trying to identify an S0 galaxy. And, it's not easy. For example, even I have trouble, at times, trying to differentiate a lenticular galaxy from an elliptical galaxy. But for the most part, I think you are all doing a fine job.
Eric F. Diaz