Renshuu.org - Study Japanese Online

the resource I'm using says with the first usage, であれ needs to follow the second noun as well - ie 先生であれ学生であれ，この規則には従わなければならない you must follow the rules regardless of whether you are a teacher or a student.

what about the であろうと - anything on that?

that one wasn't listed at all in there

In my book, it states that であろうと means even/even though. For example どんな人であろうと、良心があるはずだ。 Meaning even that person should have a conscience. The subject before であろうと is opposite of what the after statement says.  So AであろうとB is like saying "Even though A (which seemed like one way), B. Another example is 親であろうと、子供の将来を決めつけることは出来ない So even though they are parents they can't decide the children's future. You thought A was capable of doing those things however, they cannot. Something of that nature. It is a little difficult to explain.

what about [question word]であれ (誰であれ - 'no matter who' etc)? Would that fall under the second usage, do you think?