Hi,
I've gone through your your requirements, it seems clear, but I'd like to ask that, which smtp server do you use for your email server ? If it has a API, so that the email parameters can be logged or saved in by writing script implementing the API. And about email status check and open rate tracking, some tracking pixel or similar technique is usually followed.
I've very good experience in developing web application integrating better UI and API programming.
Please feel free to ask your queries about your project in chat.
Thank you