The Documentation provides following information:
If you rerun a migration from Exchange 2010, 2013, 2016, 2019 or Office 365, On Demand Migration for Email re-migrates mail, calendar, contact, task, and sticky note items that have changed in the source mailbox to the target mailbox. Also, calendar items that have been removed from the source mailbox will be removed from the target mailbox.
This means calendar items that have been removed in the source will be deleted also in the target. But for a "pre-migration" Szenario it is necessary to know if also in the source deleted mails are deleted in the target. Has anyone an information about this? Or will the mails be still available on target after they have been deleted in the source before remigration?