Hello, and welcome to SoM.
Regarding your questions:
Yes, many members on the site use "faces" or emoticons when talking in the chatter and such. It is common. If you click on "Info" above the chatter box, you will be taken to a page where there is a list of commonly used ones and how they appear in the chatter.
Concerning the other question, many members also put that sort of information on their profiles/bios if they feel they want to. You will not be banned for that.