I havent tried the scaling issue but will see if i can reproduce it. Are you scaling the parent or the child meshes? Or is this just something odd that happens?
The origin was in the middle of the blade, instead of at the middle of the handle. I changed the origin and orientation of the sword, parented it to the hand, positioned and rotated as needed, and ran the animations and it worked just fine.
**Edit - If i set the parent of a model or a mesh, it will automatically take the scale of the parent. So if the parent is being scaled by .5, then the child model/mesh would have to scaled by 2 to keep it the original size. Scaling a child model/mesh has no effect of the parent.