Ok, you are a teacher, so, with all due respect, please understand that:
--many teachers have already received some basic training in this either in college courses, workshops, Inservice, or ARD meetings
--IEPs & 504s (at least where I am) line out what we are supposed to provide.It will say something like "preferential seating" NOT "student must have a bean bag chair and yoga ball in room to choose from in addition to any desk, table, chair, etc)
--and that there are other things going on in our day and lives to tend to.
At some point we have to draw the line at accommodating every parents want. Yes I understand you see it as a need, but reading documents and attending training set up by you (not the school) is all a want. If they allow you, what's to stop the other parents from requesting such? If there is a specific way you feel your child should be handled, then YOU need to be doing/providing that through homeschool or serve as an in room volunteer to him everyday.
You are asking for what you can do, truthfully, I think the answer is to ask for an ARD meeting, go over the iep, suggest what you think, have your pamphlets, and then move on no matter what the outcome. If they don't do it, leave it be and learn to function within the environment they are providing, find another school, or homeschool.
Yes you are an educator, but in this situation you are not the diagnostician, administrator, teaching staff, etc at this school/campus for this student you are the parent.