As I was checking the questions, I noticed the waitress asking a question by using は (wa) instead of か (ka). Can you explain and how it is used as a question? Also are there other uses for that particle?
It's a different particle written 'わ'. It's a particle that is placed at the end of a sentence in order to indicate emotion and/or admiration (or emphasis in Kansai dialect [equivalent of よ]). It's usually used by females.