We have an email template design that we want a word or two within a sentence to have a different style than the rest of the line. Is it possible to create a custom line style that will appear in the Styles drop-down within the edit box's toolbar?
Similarly, we want to setup blocks that have different styling than others, so that when a heading 2 is selected in Block 2 it will look very different than the heading 2 in Block 1. Is that possible to setup on the template end so that the user filling in a new newsletter doesn't have to do anything other than to select a style?
Based on what you've described, it may be possible to do some of what you're interested in with our email editor. Having said that, it is very important to mention that the Constant Contact API does not currently have the ability to modify or customize templates for the Constant Contact email editor. At the current time, it is limited to only modifying the contents of custom code emails.
With that out of the way, I do want to mention that it may be possible to commission our Custom Services team to create a template for you that would have this behavior. If you are interested, I would suggest sending us an email to email@example.com so that we can connect you with them.