Have deleted email in Outlook become 'read'
The commercial product, ReliefJet Essentials for Outlook (I am one of its developers), has a free feature: Outlook Tweaker. It provides a Mark deleted items as read automatically feature. Just check this box and all your messages will be marked as read when they are deleted.
This is available now in Office 365.
File > Options > Mail > Other > Mark messages as read when deleted