When you clean their litter pan do you clean it completely?  If you leave a
little of the soiled litter on top they are not as likely to play in it.
 
You might also try the sand box.  This lets them get the digging out of
their system.
 
As for as food, I think that is a ferret thing.  I used to have a J feeder
that had a lid on the top.  The one the had at first didn't.  My youngest
used to dig out all the food and climb up from the bottom and open the lid.
I would close it and she would do it all over again.  I now have just a
weighted bowl.  She seems satisfied just moving it around.
 
Of course, if I didn't have the litter pans tied down, heaven only knows
where they would end up.  They love digging under them or at the sides.
Hope loves to play in the clean litter.  She will even sleep in it, but she
doesn't do either when it is dirty.
 
Try leaving a little soiled litter on the top of the fresh.  This is the way
you litter train them, so it might help with the poop too.
 
Phyllis and the three Wigglies, Faith, Hope and Charrity and soon to be one
more
[Posted in FML issue 2335]