[Ray_from_Mi]

I have a couple of questions that I would like to be clear on.
1.) When stepping on the centerline, in order to have a violation, does the whole foot need to be past the centerline? or can any part of the foot be considered in violation? Also, does this apply to any other part of the body? (i.e. hand, knee, elbow, etc...)
2.) Illegal alignment, is there an easy way to call IA? or is it as complicated as what others who try to explain it make it seem? Is alignment front to back as well as side to side? Can a front row player be behind a back row player (Rf behind the CB or RB) Does IA concern the setter as well? or is this person absolved from IA.

Any help on these two subjects would be greatly appreciated.
Thanks,