Don't panic on the etiquette
"I will observe the teacher-student, and student-student relationships. and be courtious and desperately try to avoid and mishaps in etiquette."
It's pretty straight-forward and someone should go over it with you on your first visit or class. You'll be fine. If a dojo is filled with psycho-etiquettes I'd go elsewhere (but that's me).
Look hard at the hiearchical relationships. The single biggest thing to me is if it's ok for the senior instructor to mess up. It should happen a pretty fair amount of the time if they are honest and open. Perfection is not a good thing and not found in the Aikido world.