Hi there @wlsfh,
Regarding the Welcome emails, yes that is expected behavior: welcome emails will only be triggered the first time they sign up, and switching to unsubscribed then resubscribing won’t trigger them again:
https://kb.mailpoet.com/article/360-troubleshooting-welcome-emails
Completely deleting the subscriber as you were trying to do would be necessary for sending the Welcome email again to the same address.
As for the issue you mentioned, after deleting the WordPress user, and then moving the MailPoet subscriber to the Trash, please try running the “Force sync” option on the WordPress users List under MailPoet > Lists. If the subscriber is still on the WP Users List then it would not be possible to delete them from the Trash, so re-syncing that list first will be necessary. Give it a bit to make sure it finishes syncing, then try deleting the subscriber from the Trash again.
Another recommendation, if you are testing with a Gmail address, you could try using the “+ trick” to create aliases and use those to sign-up.
If your address is “[email protected]”, you could try signing up on your MailPoet form with “[email protected]” — it will see it as a different address in MailPoet, but Gmail will still receive your emails:
https://www.cnet.com/tech/services-and-software/6-clever-gmail-tricks-to-minimize-regret-frustration-and-spam/