You asked a few different questions in post, and other respondents gave good answers to some of them. The one that seems most important but hasn't been answered is this:
>>I'm not convinced that all of the files I had stashed were unstashed. Is there anything I can do? Any way to check?
Compare stash to local tree
I think what you want to do is compare the stash to your local working tree. You can put the -p switch on the stash command and you're good:
git stash show -p
If there's a particular one you're after, just use its git stash name or id from the stash list:
git stash show -p stash@{3}
Maybe use the diff?
If you're really interested in pushing your git skills, you could always go for a diff. To see the difference between what's in the stash and whats checked into the HEAD on the master branch the following diff could be used:
git diff stash@ master
Another neat command to show you changes for elements in the stash history that might come in handy is --stat:
git stash list --stat
But I think the simple answer is the right answer. Just use the -p switch and you'll likely see if the stash you shelved has been popped back.
git stash show -p stash@{3}