I'm glad she's a bit better! Definitely sounds like a crop issue. Your plan is great!
Here's a good article to read if you haven't found it already.
https://www.backyardchickens.com/articles/how-to-treat-sour-crop-and-impacted-crop-and-how-to-know-which-one-youre-dealing-with.73607/
Her droppings are a sign that she's not eating. Try giving her eggs, meat, fish, or chicken feed made into a mash with water and see if she eats. If she doesn't, you may have to force food into her.
Early the next morning do a crop check and see how it feels. If its not empty then she has a...