Editable character body model: What way to go for?

Hello there,
I am a bit of a newbie with Unreal Engine and I hope the more seasoned among you would be so kind to offer me a bit of advice.
I am trying to go for a blueprint based - in game - character editor, in which the player customises length and thickness of a “sausage” using the “bones” of said sausage.
Here is a sketch visualising the editor:
i am currently trying to achieve this using splines, how should I proceed? Is there a way to make them editable in game? Is this the easiest way to achieve this? Are there better ways to do this?
Thanks for the help, it is really appreciated!
Have a nice day!

Idea for bone based solution:
have a joint chain be the main driver (similar to human spine bones). Have one bone below each of the driver spine bones which holds the skinning data for the model.
Use bone transform nodes in animGraph to do realtime edits on skinned bones scale values for thickness and driver bones length values for length.

Thanks a lot for your reply.
Do you think I could add bones to the chain without a problem?
Could I then attach some things to the mesh itself, e.g. some eyes, or in the mesh itself?
I know I am bothering a bit, but your reply intrigues me a lot.
Thanks again

You can attach anything to sockets inside ue4. Or in the program you are rigging in. Skeleton changes on the fly will be harder tho. Might need to change the skeleton and then update the whole referenced content in ue4.