This is a pretty basic hack, but I needed a plugin that does exactly what this plugin does, except with pending posts instead of drafts.
So I went through the code and replaced all instances of "draft" with "pending" and "Draft" with "Pending" (both case-sensitive). Then I went back through and changed some of the "Pendings" to "Pending Posts," anywhere they appeared in user-facing text instead of code, in order to make the English a little more normal.
It works just fine now, as "Pending Scheduler" instead of "Draft Scheduler."
I also added a few lines of code to list all the pending posts on the same page as the scheduler, so I can see what I'm about to schedule.
If anyone wants this code, let me know.