Also, is there anything else to Olivia's story after you find her stuck at the movie theatre? I find it weird that she's the only worker I haven't been able to feed the sandwich to.
You can feed Olivia the sandwich. No idea how many girls there are. I didn't count. All I know is whenever you hear a bell ring when you encounter 1 in public that girl can be a waitress. 15 girls total. It will go down to 14 because one of the girls leaves later on.