Developers possibly working with sensitive PII data may complicate things immensely. Ask your compliance person about what risks this introduces, and what controls and training should be in place to get dev to the same level of respect for data as operations staff.
Not doing this full copy for dev and test environments may avoid PII entirely. Have support staff build out example data, sanitized from real life examples. Import configuration and build data only, not data about people. This keep them separate approach is a lot of work to keep maintained and realistic, but keeps dev and test small size without sensitive data.
There remains a need to test full restores, if only to test the backups, per IT's business continuity procedures. Backups should be done in ways with an acceptable impact to production performance, whether export like mysqldump, replication, or block storage snapshots.
Should there be a need to transform a copy of production into a non-prod environment, in my opinion it should be a separate support or stage environment, and developers should not have access to it, only support staff. Minimizes impact of a thing in testing doing things users would notice. The full copy non-prod environment may be down for extended periods of time, because re-writing all the PII takes a long time.