I don't know anything about inkscape, so i cant help there, animation is alot of work depending on what your trying do, could you do it any easeir? moving only 3 shapes is pretty good going, its hard to see what your trying to do with the image, is it a shoulder? leg? or is it something else.

What i can suggest is maybe have your software that your using handle the images on movement, like "draw" the sprites, and when your "character" is in a certain state you could have those images layered on movement and be in a determined by the position of the X and Y co-ordinates.

But if im honest, its more tedious that way, and more problematic, just thought id share my thoughts, as you never know it might help. :)

I think Free Form Deformation (Mesh Animation) is what you need  :)

https://www.youtube.com/watch?v=OU-MkV4N67Q&spfreload=5

You can use groups and box selection. Maybe you can use a custom fill pattern but I don't know how.

Can't fix your problem. I'm looking for a similar solution myself.

• But one work to do this is to put them in a group, 
• double click on the object to enter the group,
• `control a` to select all the objects in the group.
• `F2` to enter paths editing
• select all of the nodes u want to move
• move them

I hope this helps a bit. 

-- from a fellow inkscape artist