They normally do a closing of the class, they breifly review what was went over, what work is due, and other important information. Then, "have a good day", "see you all tomorrow", "have a nice weekend (on Friday)", those kinds of things

No, No, No. It should be something a lot more formal, like: "The lesson is over. See you tomorrow the same time" or "The lesson is over, see you next lesson. Do not forget to do your homework!"

I would not use, neither have I heard any of those in a classroom setting. The first one is a kind of funny way to say :"we are done", and the classroom is usually more serious setting...(even though IT IS correct grammatically) The second one, the teacher may say it, but not as his/her last words, usually wraps up the class with other things(including home work assignments, saying :"See you tomorrow", "have a nice day", and "bye"

you can say those tow and also many others like, "okay that's all for today." or "we'll continue tomorrow" as well as "we'll finish now" etc. :)