Good question. We have been wondering the same thing. I have just been printing calendars off and using hard copies to schedule e-mails. It would be much more efficient to be able to plan right in Constant Contact.
Welcome to the Community! Thank you both for reaching out. When it comes to scheduling an email without having to create one that is a great idea! But unfortunately at this time there isn't a way to achieve this without creating a campaign. I am going to track this request and send it to our developers to hopefully have implemented in the future!
When it comes to the Outlook and Office 365, we do have a way to sync the contacts from those systems but not the calender's themselves. I do apologize for the inconvenience.
Please let me know if you have any other questions.