Best way to set up (modular) character with changable skeleton size

Basically the first three images show how my character is set up now. they all share the same skeleton and animations. however i would like to implement some limbs which are larger than others as shown in the forth image.

Im struggling a bit to figure out how i should set this up.

My thoughts of how to do this are:

  1. Should i somehow set it up so that the arm is it’s own skeleton then combine within the blue print?
    the issue: i suspect this would be a nightmare when it comes to animating and syncing.

  2. Create a separate full skeleton (with the same naming) for each possible combination of the limbs,
    the issue: this will mean creating A LOT of addition skeletons, although not too difficult it seems very wasteful.

  3. Somehow scale the skeleton bones when specific arms are equipped
    the issue: Im not sure if this is possible at run time. also getting the exact scaling may be difficult (i honestly don’t know)

For reference i’m aiming for something like the customization system in games like armored core.

Any help would be massively appreciated. Thanks.

Anyone, got anything on this??