Re: GDPR?
You're right in principle that an email address can be personal data (not "PII" - there's no such definition under the current legislation), but only if it can be associated with a personal identity by the data controller.
So AB12345@some_free_mail_service.com is probably not personal data unless combined with other information to uniquely identify a person. However, aggregating other data associated with that email address would make the entire aggregate become personal data the moment the aggregate is sufficient to identify the individual. On the other hand, an email address such as Anne.Other@some_free_mail_service.com is more likely to be personal data in its own right.
But the name is not the necessarily the issue. If I live on a street with a common postcode for 20 houses, that postcode is not personal data. Supposing I restore steam engines, that's not personal data either. But both these pieces of information together may be personal data if I'm the only one in the street that restores steam engines, even if my name is not included in the record.