You might have better luck asking in the Workshop -> Patterns, but have you tried etsy? Otherwise there's a few tutorials on youtube and tips in the Patterns topics for drafting basic patterns for BJDs (skirts, shirts, bralets, socks, etc) that can be adapted once you've drawn out the pattern! Or you could probably find a similar pattern for a thin doll and tailor it to your Popovy!
Either that or maybe ask in Workshop: styling and crafting. Hopefully someone will be able to help you there! Maybe there's a fashion doll of a similar size that has patterns available you can adapt? I'm not very familiar with them myself, but if you post a question there, someone might know!