Currently in order for a webform to appear within a teaser displayed post is to configure each and every webform independently. :( Super Sad Face :(
Desired behavior would be that when "Node Content > Full Content" is configured within DD Classes, the webform should display along with everything else that would show on a full post display.
Great idea, Jason! It seems like the presence of the class should force the appearance of the form in that particular context, as you suggest.
This is especially important for overviews. WEAVE ran into this issue when dealing with overviews in mobile.