It ended up like this--it's still a pretty odd wrap-style shirt, but at least I know where to alter it, and the shirt is at least wearable so Erzulie has something of her own. Here's how I put it together, more or less--I just eyeballed the pieces, which is why the fit is so odd--no measuring was involved.
I ended up trying it under a pretty dress that Rajendora sewed me for a gift, and while it looks ok around the collar, the shirt is really too bulky to layer "as is".
So Erzulie has a cute little dress to wear as well--I think I will make a little leather belt to match it later. Rajendora made a second dress as well, this is it on Gemma--it's really adorable!
Thank you so much, Raj!