@sfss is right for #1 & #2. While people can respond to an email blog post, you can only reply to these messages with your own dedicated email address.
#3 can be accomplished with some JavaScript. Here is what you could use:
// Removing text from Email Sub
if (document.getElementById("emailsub") !== null) {
var esub = document.getElementById('emailsub');
var text = esub.getElementsByTagName('p')[0].innerHTML = '';
}
From there you can add a custom message in the post above the <!--emailsub-->. If you don’t want it to be blank but a different message, you could replace the text with your own custom message like so:
// Removing text from Email Sub (with custom message)
if (document.getElementById("emailsub") !== null) {
var esub = document.getElementById('emailsub');
var text = esub.getElementsByTagName('p')[0].innerHTML = 'Add custom message here';
}
As far as #4 goes, there is no option to access your blog email list right now.
Hope that all helps @writedirt . Do me know if you have further questions from there.