Yeah! It is great opportunity, I remember from in 5th grade I dissected a squid. We had to wear trash bags over our clothes and had to wear masks on your face an goggles. I had to go wash up after class.
By all means let them do it. Be sure they are aware that they will be seeing the bones of little animals (I do not know how old you child is and some can be upset seeing something like this). It is a great way to show how the food chain works. Fish are good for teaching this too, esp bottom feeders.
Sure. Why not? Rabbits are herbivores so its all vegetable matter and im sure theyll be wearing gloves. In high school i cut open a worm, a crawfish and a frog. My fav memory was disecting a cows lung in fifth grade and using tiny milk carton straws to make chunks inflate. We carried chunks of cow lung all over the school showing people (it was a small school at that time). It was awesome.
I guess it depends on how well your child would like it. When I did it, I was happy to do it because I enjoyed learning about animals, and I still do. If your child is squeamish, or doesn't want to (Because they truly don't want to, not because they don't feel like it) then don't do it. I will say thought, I benefited a lot from it. After I dissected it, I put an almost entire skeleton together from the mouse bones. It helped me learn a lot! So by all means, do it, and enjoy it!