Ask your principal to attend the next staff meeting and ask the teachers in person. By appearing at the meeting, they would feel that you really do care. If not everyone speaks up, offer them to send in their ideas within the next week.
However, I feel that if the teacher has special needs, they should speak to their Head homeroom mother rather than the PTO. The room mom turns over year after year and the amount of time that mom has to offer changes as well if they work or have siblings still at home. For the PTO to create guidelines would turn it in to a job and it may turn off mothers from volunteering.
If you are asking the teachers, ask on behalf of the entire PTO; not just the one committee or as coordinator of the homeroom mothers.

1-What areas would you like to see us improve?
2-Do you have concerns with any volunteer issues in your room?
3-If you could have us do one thing, what would it be?
4-What times and days are best for your classroom to have parent helpers?
5-What one thing would you change with parents in your room?

Hi, I am new to this site. I handle the Teacher Appreication for our PTO. I am working on a teacher survey to get ideas about how the PTO/homeroom parents can better serve/help them individually. Any ideas on the typed of questions we should ask? Thanks