I would wet the crumble to a mash just to make it easier to eat. I find that most chicks get more excited about mash then dry crumble as well. Try to get some Nutri-Drench, probiotic powder, and electrolytes. The probiotics are immune boosting. Since most of the immune system is the gut, adding probiotics support the good bacteria, boosting the immune system. You can do 50/50 Nutri-Drench in he drinking water, make sure to offer plain water on the side.
The only problem I see here is that Hope is a lone chick. Chicks do SO much better with another chick. They show them how to do things, and it makes them much easier to integrate. Stuffed animals work well, but having a lone chick is never ideal. Not sure if you still have chicks in feed stores in your area, but if you do, maybe explain to them that you have a lone chick, and would like to purchase one (or more if you can fit it) for Hope.
You could also try to give her back to the broody, but this doesn't always work.