I would go with an assumption that she is copying her lawyer on everything she writes to you
so
use that to keep in mind that anything you write to her will also be on record
there is nothing to settle with school...I agree with Alice... a to the point email, short and leaving no wiggle room is best
or you could ignore that part contact a mediator and try to schedule a time where you and your wife could hammer out some details (like school stuff then...contacted mediator (insert name) about scheduling a time to go over everything...such and such a time is free. We can meet then...let them know at xxx-xxx-xxxx.
watch letting your daughter act like a turd...she will manipulate your guilt to her advantage...not because she is evil but because that is what kids do
also
no need to tell parents you are splitting just a "hey...we should get the daughters together this summer...here is my email."
unless they are good friends of yours, anything else might be too personal.
i mean you wouldn't go up to your pharmacist and say...hey..skank and I are getting a divorce so I thought I would give you my new phone number in case you want to talk to me. And I need a refill on my meds"
it is not necessary to share details with people you wouldn't normally anyway