Yes, symbol is just a wrapper with a timeline.
What I do is put all PNGs for a character as frames in one symbol. I also mask them so that selecting with KineFlex works better.
Then use this symbol to put inside other symbols.
If you need to do edits, re-import and so on, you only have to deal with your master container.
The power of Flash comes from using nesting in creative ways.
I've been thinking to do a tutorial about a real paper cutout workflow, but it may be a few months away.
We did some tests last year.
Some pictures here.
And some video here and here.
Hope this helps!