You can use VentoryOne to submit a variety of SKUs within a Send-In to your logistics provider. This means that there is no direct field with an individual delivery ID that you can insert in the subject or in an email template.
This would result in the content being too long for multiple products.
You can store a note for your SKUs, within a Purchase Order, which you can display in the FBA Send-Ins. You can insert this note into your FBA Send-In name via the settings.
Finally you should use the placeholder *|FBA_SEND_IN_NAME|* in the email or your subject.