Preferably by September 1st.
Yes, it is a semi-formal event so please wear whatever is comfortable to you. Please keep in mind that it is in October in Michigan so it will still be warm in the day but you may get chilly at night.
While we do love kids there will be alcohol involved so we would prefer you kept them at home unless told otherwise.
If you have a good allergy please let us know so we can try to make accommodations and label the food items that have that specific allergy in it.