Hi britzl,
I think I am looking for any person 
Another developer would be great to share knowledge about Defold, to progess quicker with game features and some more platform specific integrations like video ads and so on.
An artist is also great to separate things. I am artist too and drawing GUI and other things is very time consuming.
A game designer is always a good match. It takes as much time as programming to write it down what about is the game itself, which achievements it can have, and what attributes have all the items.