I've always taught my classroom expectations first. To me they lay the foundation of what's required to be successful in a classroom setting. Coming from a self-contained, special education background, where class community is paramount, I couldn't imagine teaching a piece of a procedure for the school at large on day one. My thing is, before you can even be part of a community, you need to have an understanding of who you are and what your role is.
I get the other side-- it is important to show a united front-- but I think it'd take much more planning to pull off a seamless day one of each teacher, teaching a part of all that a student needs to get through the school day successfully.
Regardless, just make you sure teach routines and