Contact a child disability advocate. Go through the state if you must!

Sorry for the late post, but from your message your meeting has not taken place yet. To become knowledgable in the process of what should take place go to wrightslaw.com and put discipline in the search box. The 10 day rule applies to days suspended, not number of suspensions, so if your son has exceeded being suspended for more then 10 school days in one school year a manifestation determination meeting must take place. What this basically means is was the behaviors due to your child's autism. Was the IEP followed leading up to the suspensions ? Was appropriate behavioral supports put in place after a number of behavioral outbursts? There are many things the school system must do when behaviors occur. Please, please go to the wrightslaw site to get a good understanding.
In my personal opinion, it does not sound like the staff is trained in behavior management.

I believe it is 90 days or something like that, ridiculous!
I would get in contact with Easter Seals or some type of organization like that to find out resources in your area for a free consultation with an autism knowledgeable attorney, before the meeting.
Have you ever looked into supplements for your son and specialized diets? I put my son on a GF/CF diet plus probiotics and enzymes and a lot of the rage died down. He still has his moments of anger or frustration, but it is not nearly has intense. If interested, talk to a DAN doctor or a holistic doctor, they are great!

I believe there is a time frame in which the school district has to respond to your IEP request. I know at all IEP meetings we attend for our son, we are given the 'regulation' forms/paperwork (we too live in MN). If not, call the school district special ed dept and have them email you one. It may be best to contact an attorney.

I've never had to deal with this situation but I know that there is a procedure in place that I think is called a manifestation determination. Basically it determines if the behaviors that caused the suspensions are caused by your son's disability. If that is the case there needs to be a behavior plan developed. Also with ten suspensions there is the issue with change of placement.

It could not hurt to consult an attorney or advocate who knows your state laws and could advise you. In the meantime you can go to the wrightslaw website and look up suspensions and manifestation determination.