I'm going to suggest a list of topics to be considered here and then leave it up to your good intelligence to fill in the blanks and distribute as necessary to those who need this information the most.
Use caution when you distribute this information. Make sure the person you give it to treats it as Personal and Confidential. Consider providing a copy for your ex, his parents, your parents, your children's school and your children's child care provider. Omit information not needed by the one you give it to - social security number, for example. In our era of Identity Theft, it's wise to be cautious. Mark the file as Confidential Information.
Child's Name
Date of Birth
Current age
Sex
Social Security Number
Allergies
Doctor's Name
Custody Options/schedule - weekly, vacation, holiday
Homework Agreements
Primary Residence Address, Phone, Cell
Secondary Residence Address, Phone, Cell
Exhange Agreements
Who has permission to pick up from school?
School, medical, and court records sharing
Communicating Emergencies
When a parent is moving
Activities - scouts, little league, dance classes etc.
Transportation
Dating Considerations
Extended/blended family Authorization for medical treatment form
Communication between divorced parents can be very challenging. If it's at all possible, and to avoid confrontation, make an effort to communicate in writing. If you create the above form, it should help smooth out a lot of bumps. By using specific fields above versus writing large paragraphs of data, you can avoid miscommunicating.
Be courteous when you communicate with your ex. Keep it factual. Your children deserve to know that at a minimum, daddy and mommy can still speak to one another civilly.
Ask the school to send notices to both parents. You both need this information. You both need to read it and make yourself aware of what is going on with your child, particularly if you share custody across the school week.
If the information and communication sharing causes flare-ups of your emotions, please don't share these emotions during communication interfacing. Use a friend's shoulder, or address it with your ex at a time other than when you need to communicate important facts about the children. Use common sense; be mature and save the emotional communicating for another time.
Another practical tip: don't count on your children to carry this information to your ex for you. Be a big girl/boy and do it yourself. It's a burden for your children and they don't need that from you. Communicate this parenting plan when those little ears cannot hear you so as not to bruise their souls.