Hi @SuzyK ,
What I what consider doing here is having my students in an excel table with name, email, startdate, and mid-year columns. The mid-year column can be a simple excel formula that writes the desired date based on their start date.
Create a array variable.
Next you can List rows present in a table with a filter query that says
mid-year eq '2023-07-31'
This is going to give you all the students that need that July 31st evaluation.
In your for each loop you want to loop through the rows and add the student email addresses to your string array with a ';'. This will end up giving you a string array of tom@somwhere.com; mary@somehwere.com; jim@somewhere.com , etc
Then at the end, below my apply to each, I create my event and the attendees are my string array.
I would have to create this and maybe clean up some steps and/or redescribe them but that's the general process.