Kittens 8 weeks and I have questions

Our kittens are now 8 weeks old. We are ready to give them away but they are not quite ready to go. One of them drinks water but will NOT eat food. Another one eats food but will NOT eat cat food. The little stinker steals food and runs off with it. Such things as bologna sandwiches and donuts. One of them eats eats and eats all the time. But now has diarrhea. The 4th one eats and drinks but will NOT use the litter box. What should I do. Each kitten has one thing that is keeping them from going to it's new home. They are like little rats running everywhere. So funny but always under your feet. Climbing up my leg until I pick it up and love on it. They discover the rest of the house so all night they are clawing up the sides of the beds. How can I get these little guys all ready to go? The vet gave us wormer for them but none of them will eat it. AAGH!! I though my kids were impossible to deal with!

Well, first I dont remember if you have mom. If you have mom, my best suggestion to you is to put them in one small room with her. Kittens learn most of everything they know from mom. If mom is out running around, they are not paying close attention. Especially if they have the run of a large house. They almost have to be forced to use the litter as well as given only a choice of cat food.

She was pregnant when we found her. I was doing the opposite as you suggested. I was putting her up in another room so they would quit nursing so much. I never thought of the other things like litter teaching and those things. The biggest kitten nurses all the time. Never eats cat food. What's with that? But then again she never covers up when she uses the litter box. I even tried to show her how.
Plus, what is the best litter to buy for these little guys? I love the crystals but I was afraid they would be toxic to them. What do you think?

The crystals would be okay, they are almost the same as the clay litter. The scoopable you want to stay away from because they will eat it and it will clog them up. You might want to try the clay though. I find that most kittens like to bury it like mom.
Yes, being a breeder(trial and error) with kittens. The very best way to teach them is to make them watch mom. I had kittens pooping and peeing everywhere because I gave them too much freedom. Don't worry about weaning just yet. Mom will usually do a very good job of this. If you watch her, she will keep them from getting to her. Cats by instint want to teach their young to fend for themselves. Besides, it is in the kittens best interest to stay with mom until 10 to 12 weeks. They will be so much more well adjusted and have more mannors for thier new families. I promise, if you force them to take on moms habits, they will. So make sure they watch her eat, sleep, use the bathroom, groom, play..etc and they will start doing the same things.