I agree, I would also leave the crate out for Denali. I'd also only give them treats while in there own crates if treats were a cause for fights in the past.
Congrats on having her back. Hope everthing turns out OK.
Here's a great link on how to handle multiple dogs in a home. It helped me understand a few things.
http://www.geocities.com/Augusta/2525/multidogs.htm