J.P.
You could try some canned food for kittens...they also make a milk for kittens and cats that's in the pet-food aisle that might be nice to mix with the food (either wet or dry). Then water can be offered in a bowl on the side. We had a kitten that liked to suck/nurse and we would dip a facecloth in milk or water and she would suck forever on that thing. They say regular milk isn't good for cats, but all my kitties have always loved it as a treat. I dunno'...I'm not an expert. He's going to be fine with whatever you do, but with little baby teeth, softer food is best.
As for the ferret, I would do a face to face intro with one of you holding the ferret and one holding the kitten...let them see/smell each other...the kitten will grow up knowing the ferret is a friend, so its up to the full-grown animal, the ferret, to get acquainted/accustomed to the kitten. I have seen people have both ferrets and cats in the same house, but I don't know how long it took for them to be okay with each other. I would keep kitty's things and food bowls far away from the ferrets things so territory issues don't start..and have frequent meet 'n greet sessions between both animals with supervision. Good luck!