Usage and Grammar

Q. I work for a software company catering to law firms. In a law firm’s name you might use “et al.” if the firm name is long. What is the proper way of doing so?

Q. Could you please tell me the difference between toward and towards?

Q. What is the proper use of “would” or “could” in sentence structure? For example, would you please close the door? Or, could you please close the door?

Q. A number of educated friends tell me that “sans” is archaic and affected; they frown when I use it and instead encourage “without.” What do you think?