Hi Isotta! I received the announcement you posted today to my mailbox. It did not go to Spam, but depending on how your students have set up their e-mail acccounts, it might go under Updates tab. (this happened in my case also). If it really goes to Spam folder, you could ask them to (again, depending on their e-mail settings) to add the firstname.lastname@example.org to the list of approved contacts or create an appropriate filter.
I will get back to you regarding students' e-mail addresses! Thanks!