Do you need to have your character in layers (svg/psd file) in order to add animations to it ?
(2D)
If you mean animating it with rigging no, and its also no for sprite to sprite. A png file is ok. But i am not sure i exactly understood your question. Can you add details?
just export all the layers as separate png’s and then put them in a parent object in unity and you can rotate all the parts when animating.