Here's some concept art for how Lefty will look. I've purposefully designed these characters without thinking about armatures. I don't want the thought of how it will work to get in the way of how they should look. Their shape is fine in 2D, the challenge will be to create the armature to make the 3D shape as similar as possible.
There are two main problems with this design. The first is the size of the head. She looks really cute but the actual puppets will need a smaller heads to be able to interact. I want them to be able to hug each other in a realistic way and not have their contact restricted by their bubble heads. The second is the thickness of the arms and legs. The size of the ball joints will dictate how thin they can be but I will try to keep the aesthetic of this concept design as best I can.
The plan is to have a knitted skin for the puppet around a ball and socket type armature that is stuffed with wadding. I'll flesh out the shape with polystyrene but I want them to look like little sack people. They need to look like they have weight while standing still, hence the volume being around the belly, the hands and the feet. To discover what knitted string looked like I made this...
It was my first attempt at knitting and all those Hollywood actresses are right, I found it very addictive. Part of me thought I should've attempted something a little more useful than a square but I was happy to hear my Nan say that they used to knit dishcloths out of string and sell them at fates. I don't think mine would fetch much though. Anyway, the point was to find out how string moved when it was knitted. Surprisingly it seems like a good material to use for a puppet. It has enough stretch to enable movement and is tensile enough to keep the puppet's shape. Even though I would love to knit Lefty and Righty myself, it's just not practical. The reject dishcloth took me a whole day to do and I'd have to learn how to knit more than just squares, so the idea now is to find a ready made knitted garment that I can cut up and stitch together.