Check out VGC software's VGC Animation[1].
The author, Boris Dalstein, published a novel algorithm for shape morphing at SIGGRAPH 2014, using vector animation complexes[2], which is the basis for this software.
AFAIK this is (still) state of the art for this stuff today. I.e. I haven't seen anything better if you do any sort of 2D animation based on vector graphics. Topology is more or less not a concern any more.