replace character mesh with new one, or transfer components from old to new mesh

I have a prefab object of a character that has multiple colliders and components attached to each child (in this case bones like hand, hip, etc.) The mesh has some problems so I had to output a new mesh. Can I replace the mesh of a character with another one. I tried to change the mesh in the component with the new one but it disappeared.

If I can't replace the mesh is there some script to automatically copy and paste all the components from one hierarchy to another or do I have to do copy/paste each child by hand. The asset store has a copy paste components, but it does looks like it will only copy one gameobject at a time. The character hierarchy has about 30 child game objects.