In 4), what you describe about sending email to a mailing list is not clear to me. Are you saying that the mailing list will have a public key that’s used for e

In 4), what you describe about sending email to a mailing list is not clear to me. Are you saying that the mailing list will have a public key that’s used for encryption (by the original sender) and that the mailing list software will decrypt and re-encrypt with the public key of each member when sending the emails? If yes, then if some members don’t support receiving encrypted emails, those would certainly go unencrypted. In other words, there’s no guarantee (except in small and close groups) for this to work as intended.