What do Japanese foreign teachers say before and after class?

Correct the first floor. You can't use "さよぅなら" here. We don't usually use this word in our major unless we say goodbye to our teacher after graduation. This word is only used when we are separated for a long time (even when everyone is dead).

Actually, it doesn't have to be so formal at all Japanese people are not as rigid as you think, especially young women nowadays, who are mostly easygoing.

"ぉつかれさまでした" on the second floor is also inappropriate. It is often used among colleagues, so you just need to express your gratitude to him between teachers and students.

Say xxxですですどぅぞよろしくぉはじめまして for the first time. Just do it, don't be too official, it will make the other party feel far away.

When you enter the classroom again, say "こんにちははぃですねねねね". Do it. Of course, you don't have to say that the weather is fine every day. It's a little strange that you want someone to tell you "it's a beautiful day" every day. Simply say hello, if there is anything that day, just simply mention it. Don't be too formal

She answers whatever she asks, and there are no fixed pleasantries.

Say "ぁぃがとぅござぃました" when you leave. じゃね。 Just do it. You are very welcome.

You are the same age as the teacher, and both are women. Contact for a long time, you will feel that teachers are like friends, nothing.

We have a female foreign teacher in her thirties. Although she is 10 years older than us, she is like friends with us. You can talk about anything at ordinary times.

Relax, come on!