A few grammer and writing questions

Hello, thank you so much for your time!I have a few things I'm not so sure about while writing a book, please let me know if you can help: 1. Is it ok to use a dialogue quote for something said by a bunch of people at once? like: "Good luck," they said. is there a better way to do that or is that alright? 2. throughout the book I refer to a person along with his title, like this: "Emily the nurse". should I put a comma there? "Emily, the nurse" What about when writing it in a dialogue?: "How are you feeling?" asked Emily the nurse. or should I write: "How are you feeling?" asked Emily, the nurse. I think it's better without the comma, since It's a repeatitive thing- almost like her name in the book is Emily the nurse. But I'm not sure if that is ok to do. 3. Is this sentence ok:"Many tables, small and big, were scattered all around the front yard." The many tables part sounds a bit off. Does it work? Thank you so much again!!Have a great day