You must send the required fields and if you use an additional matching ruleset you must provide that element or the transaction will fail. That said, when searching for an individual in the data sources it is always more helpful to provide as much data as you collect. The more information we have on a person, the more people we will find.
No, Veratad does not store any sensitive PII information from your request. The only exception to this rule is when you use the document storage service.
Since Veratad does not store sensitive PII it is important for you to send a unique value in the reference field with each request. This will help for reporting and audit trail purposes.