I've hatched turkeys before. I kept them for a couple of weeks and then gave them to my friend who I hatched them for. They did great! Now, keep in mind that my friend has raised hundreds of turkeys and as soon as she got them, put them on water with antibiotics. She says that turkeys are so susceptible to EVERYTHING, that it is the best way that she can raise turkeys. IDK... That's just her experience.
Do you think the turkey babies would be too big to keep with the chick babies? I guess it would depend on the breed and age of the chicks, maybe?
As far as learning to eat and drink, I imagine that dipping their beaks in the water and showing them where the feed is will be enough.