Do radically small apartments automatically beget a transient population and all that entails? That’s the fear of residents in the Kips Bay neighborhood of Manhattan, the pilot site for a new building that will be 75 percent micro-units, or apartments that total about 300 square feet each. Community Board 6 finds it hard to imagine that anyone other than students or elves would be game, but City Planning Commissioner Amanda Burden is charmed by the diminutive plans, stating at a recent presentation, “I think you’ll all agree that the apartment behind me is some place that one and two [person] households would be delighted to live in.”