So-called granny flats are detached second units, like converted garages or guest houses, that homeowners build on their properties. City officials are scrambling to come up with new rules for these structures, after a lawsuit recently threw them into legal limbo. On one side, critics say allowing more and bigger granny flats could destroy the character of some neighborhoods. On the other, supporters argue that granny flats are one way to ease LA’s affordability crisis.