After deleting multiple leads I attempted to use getLeadActivity and getLeadChanges to get DeleteLead activities but neither call returns anything. I've noticed that the DeleteLead activities appear under the campaign results. Does anyone have experience getting DeleteLead activities from the API?
I don't think you can retrieve delete activities using getleadActivity, because the lead that was deleted does not exist anymore. There is a slight change that you can use getLeadChanges, which will get all activities of a particular type for a specified period. However, I've never tried this particular use case myself.