I have several Adobe Illustrator logos I would like to pop into Blender's Grease Pencil utility to animate them. Is there a good way to do this that won't have me re-drawing everything in Grease Pencil?
In short... You can't. PNG images are only images. You can't animate them in any program without previously rigging or doing most of the work by yourself. There is an addon called Import Images as Planes that allows to import PNG images to blender as a plane in a 3D space. I could see a little animation made this way. But png to grease pencil is pretty much impossible without transferring this manually to curves or redrawing it yourself.
Hope this helped.