A. Yes, it can send emails to everyone including suspended members. There is an option where you can select if it should include suspended Members or not (and also an option to email only suspended Members).
A. Yes, there is a section called "Manage Email Templates" where you can create email templates to use multiple times.
Once you've added an email template, you can use it by clicking the red email icon in the editor.
A. No, there is no need for you to stay logged in any longer for all the emails to be sent. As long as you reached the page saying how many emails are in the que the que will process on it's own without you being logged in.