Transitions between Frames

I'm kind of a newbie to Davinci Resolve and to video editing so please be patient (Same goes for my bad English).

So I want to do an cartoon as part of a Homework.
I got everything I need: A background, snowfall as part of the cartoon and a moving rabbit painted (or better copied) by me in 14 different pictures (Just for test purposes). Until now everything works fine. The problem are the frames. I really don't want to paint ~24 pictures per second so I decreased the FPS to 12, but now as expected it is really choppy.
Is there a way to kind of add a transition between each frame?

There is not. You'll need to fire up that brush and paint more images.

lots of vintage cartoons are done at 12 or even lower.
If the story is good, 12 vs 24 does not matter a bit. I rather see a well crafted 12fps than a half finished 24 fps.

You can try using the retime function using flow to interpolate the intermediate frames. If flow causes too many artifacts try the blend setting instead.