You dont have to eyeball things from a single image, even if you want to replicate it perfectly. I think you should collect way more reference pictures and use those.
So if you want to create this painting in 3d, you should collect loads of reference for human anatomy, proportion, expression, hair etc…they dont have to be the same as in this painting just kind of similar and you can use them to fill the gaps which you cant see on the painting. For the cloth, collect a lot of reference pictures of folded fabric, have another reference for the flowers, walls, floor and so on.
The best way to do the cloth would probably be Marvelous Designer, I didnt try it myself yet but it looks pretty amazing from what I saw about it.
