As I said a few minutes ago in a question, this will be fixed in 2.4. Currently working on same issue.
This will be fixed in 2.4
Its already exist in user profile -> subscription. You can check template in user/subscription.php
Did you tried this POT ?
Its tags issue not recaptcha. You must add comma after a tag. This issue has been fixed in latest RC version. You can download from our Github repository.
You can add this filter to your theme functions.php https://gist.github.com/rahularyan/71c58990809628abc9df