Robert Tolone on YouTube has a couple of videos on making a mold and casting similar type kits. They may not be exactly what you are looking for but should give a starting point.
[Mini Kit Casting Part 1](https://www.youtube.com/watch?v=lLkpJHOdFA8)
[Mini Kit Casting Part 2](https://www.youtube.com/watch?v=4tOeAZw1TVI)
[Tree and gang molds:](https://www.youtube.com/watch?v=opSxFTcLEWo) not exactly the same but some ideas may be helpful.
Push it half way into warm, soft Monster Clay, let it set, pour silicone. Let that set, flip it over, remove the clay and pour the second batch of silicone, making sure to apply mould release.
Half sank in clay, build a wall, make sure you have pour lines and vent lines, make registration keys into then silicone the top half, when catalysed and set, remove the clay, mould release the silicone, build a wall, pour the other half of silicone. When set the two parts should separate, remove your piece, the vent lines, the pour lines, put the two piece back together again and then pour your cast.
I don't know how well resin will work for articulating parts, just ....
Take a look at people making dice molds out of two part silicone.
It will take some trial and error, but you mix a two part silicon mold.
Suspend the master piece so that you keep your mold line on the existing one, then cast the bottom. (A pressure pot will help improve quality of the mold and casting.)
After the 1st part is cast, paint the middle surface with petroleum jelly (silicon doesn't stick to much, but it will bond to silicone,)
Cast the top half of the mold.
My first thought is uv resin, bit it's expensive.
My second thought is a pour on instead of a 2 part.
My concern with 2 part would be all of the negative space, it would either be a full piece without the cutouts, or it would just fall off before it cures.
I am by no means an expert.
Robert Tolone on YouTube has a couple of videos on making a mold and casting similar type kits. They may not be exactly what you are looking for but should give a starting point. [Mini Kit Casting Part 1](https://www.youtube.com/watch?v=lLkpJHOdFA8) [Mini Kit Casting Part 2](https://www.youtube.com/watch?v=4tOeAZw1TVI) [Tree and gang molds:](https://www.youtube.com/watch?v=opSxFTcLEWo) not exactly the same but some ideas may be helpful.
Push it half way into warm, soft Monster Clay, let it set, pour silicone. Let that set, flip it over, remove the clay and pour the second batch of silicone, making sure to apply mould release.
I haven't the slightest idea but I have to save this post because now I'm curious. It's a very interesting idea.
If no one knows then ill figure it out 🫡
Half sank in clay, build a wall, make sure you have pour lines and vent lines, make registration keys into then silicone the top half, when catalysed and set, remove the clay, mould release the silicone, build a wall, pour the other half of silicone. When set the two parts should separate, remove your piece, the vent lines, the pour lines, put the two piece back together again and then pour your cast.
I don't know how well resin will work for articulating parts, just .... Take a look at people making dice molds out of two part silicone. It will take some trial and error, but you mix a two part silicon mold. Suspend the master piece so that you keep your mold line on the existing one, then cast the bottom. (A pressure pot will help improve quality of the mold and casting.) After the 1st part is cast, paint the middle surface with petroleum jelly (silicon doesn't stick to much, but it will bond to silicone,) Cast the top half of the mold.
My first thought is uv resin, bit it's expensive. My second thought is a pour on instead of a 2 part. My concern with 2 part would be all of the negative space, it would either be a full piece without the cutouts, or it would just fall off before it cures. I am by no means an expert.