Yes. I am a firm believer in adding the phrase “and all other duties as may be required” to all job descriptions.
The “expediter” job should fall on a manager if necessary.
As a line cook I have had to do other things besides cook.
Bathrooms usually fall under the auspices of the dishwasher or waitress.
I know of at least one server who has experience as a line cook and bartender. Has both RAMP certification and ServSafe cert. A place she worked at, and left, failed and fails to properly pay for duties not under a server definition. As in, she was tasked with filling in on the line for two nights and was still paid as a server. Management refused to properly compensate and she left for another job. She was simply told that since there were no “records” of her doing line work, it was her word against theirs. Abuse in the industry seems to be rampant.