We are notorious for inviting drama in then expecting it to me anything other then what it always was.
Not that you intentionally invited drama but the results of his behavior are very well known to you and must always be kept first and for most in your mind.
You opened the can of “information worms” by asking him about something other than the children so he is responding back with same, electricity, check, closing. Kind of like you opened up a conversation and he’s responding.
I wouldn’t email him and say per the custody agreement – he already knows what the agreement is. I would simply send a separate email not a reply one but a brand new one and say – let me know your intentional regarding this coming Wednesday night with the children. That way none of his nonsense is part of it.