Yes, tell the school, they are your partners in the process, and will find out when they have to fill out questionnaires.

Yes, tell the school that this is your concern and ask for supports now, just as other kids receive. They can’t help if they don’t know.

Usually an ADHD evaluation includes teacher questionnaires so the teachers will know. You want them to be candid about any issues they see when filling them out.

Does your child ask the teacher to repeat that info before leaving class? "I am sorry, I was finishing writing my notes from the lecture. Would you please tell me what the assignment was or the due date or whatever info might not have been written down."

What's the advantage of NOT telling the school? You know some steps that would help your kid, whether or not there's an official diagnosis. The teacher isn't legally obligated to provide any accommodations without a diagnosis and plan in place, but surely a good teacher would find this useful context and be happy to work with you/your child as far as practical on the basis of executive function struggles regardless of DSM criteria...

We are getting an ADHD/other evaluation next month. I see clear areas where my kid will benefit from teacher support that would not be giving her any type of edge over other students and that do not seem to be adding burden to teacher loads. e.g., helping kid understand assignments - due date and requirements, in particular. She often misses those entirely. It takes her a long time to take notes, and she thinks that part of the reason that she is missing these things is that she is still writing class notes when others are able to listen in "real time" and get assignments details and updates. Teachers don't post everything to the online portal, so it is often a guess as to what is due when. This would seem to track what I know of her in daily life -- she is often 1 - 2 steps behind in group conversations and tasks.