This depends on how you configure Universal Email.
In the Universal Email wizard on the first page, The Email Body section Allows you to create the email that is being sent.
this can be done a few ways, You can Create a static html page before hand that contains the email message content, then Check the "Create a File For Your Email" option, click the folder icon and browse to the file you created.
This sounds like the option you would use to send your flier.
Another option is to select to use one of the predefined templates, this is used if you have a form and you want the form contents to be sent in the email.
you could also click the Dreamweaver icon to use Dreamweaver to create your message.
Which method to use really depends on what you are trying to accomplish.
All of the things you state you image can be done are true, the steps for accomplishing this are very much dependent on which of the those you chose to include in your application.
in reading your post, there are 9 different tutorials that we would have to write for each of the scenarios you mention. If the tutorial where not broken into different ones, it would become way to complex to follow.